EngO is a non-cellulosomal glycoside hydrolase family 9 (GH9) endoglucanase from Clostridium cellulovorans. Unlike cellulosomal cellulases (EngK, EngL), EngO lacks a dockerin domain and is not incorporated into the cellulosome complex. Instead, it functions as a free secreted enzyme with its own carbohydrate-binding modules (CBMs) for substrate targeting. EngO contains a GH9 catalytic domain, CBM (CenC-type), and Ig-like domains. It hydrolyzes internal β-1,4-glycosidic bonds in cellulose, releasing cello-oligosaccharides that complement the action of cellulosomal enzymes.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
|
GO:0000272
polysaccharide catabolic process
|
IEA
GO_REF:0000043 |
ACCEPT |
Summary: This annotation is correct. EngO is an endoglucanase that directly participates in polysaccharide (cellulose) catabolism by hydrolyzing β-1,4-glycosidic bonds.
Reason: As a GH9 endoglucanase, EngO directly catalyzes the breakdown of polysaccharides. This function is well-supported by GH9 family characterization.
Supporting Evidence:
file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
Hydrolyzes cellulose to cello‑oligosaccharides that feed uptake/processing pathways
|
|
GO:0004553
hydrolase activity, hydrolyzing O-glycosyl compounds
|
IEA
GO_REF:0000002 |
KEEP AS NON CORE |
Summary: This annotation is correct but generic. EngO has hydrolase activity on O-glycosyl bonds. More specific terms like GO:0008810 (cellulase activity) better capture its function.
Reason: This is a true parent term of the more specific cellulase activity. It's correct but not the most informative annotation for this enzyme.
Supporting Evidence:
file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
GH9 endo-β-1,4-glucanase that hydrolyzes internal glycosidic bonds in cellulose
|
|
GO:0005975
carbohydrate metabolic process
|
IEA
GO_REF:0000002 |
MARK AS OVER ANNOTATED |
Summary: This annotation is too general. EngO participates in cellulose catabolism specifically, not general carbohydrate metabolism. More specific terms exist.
Reason: This parent term is overly broad. GO:0030245 (cellulose catabolic process) is the appropriate specific term for EngO function.
Supporting Evidence:
file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
EngO is a GH9 endoglucanase that cleaves internal β-1,4 linkages of cellulose
|
|
GO:0008810
cellulase activity
|
IEA
GO_REF:0000002 |
ACCEPT |
Summary: This annotation is correct and represents a core molecular function of EngO. As a GH9 endoglucanase, EngO has cellulase activity that hydrolyzes cellulose.
Reason: EngO is a GH9 family endoglucanase with demonstrated cellulase activity. This is the appropriate molecular function annotation.
Supporting Evidence:
file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
EngO is a GH9 endoglucanase that cleaves internal β-1,4 linkages of cellulose, generating cello-oligosaccharides
|
|
GO:0016787
hydrolase activity
|
IEA
GO_REF:0000043 |
MARK AS OVER ANNOTATED |
Summary: This annotation is too general. EngO has hydrolase activity, but more specific terms like cellulase activity better describe its function.
Reason: This is a very broad parent term. GO:0008810 (cellulase activity) is the appropriate level of specificity for this GH9 enzyme.
Supporting Evidence:
file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
GH9 enzymes are typically inverting endoglucanases
|
|
GO:0016798
hydrolase activity, acting on glycosyl bonds
|
IEA
GO_REF:0000120 |
KEEP AS NON CORE |
Summary: This annotation is correct but not as specific as GO:0008810. EngO acts on glycosyl bonds in cellulose.
Reason: This is a parent term of cellulase activity. It's correct but less informative than the more specific GO:0008810 annotation.
Supporting Evidence:
file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
GH9 enzymes use an inverting acid–base mechanism to hydrolyze β-1,4-glucans
|
|
GO:0030245
cellulose catabolic process
|
IEA
GO_REF:0000043 |
ACCEPT |
Summary: This annotation is correct and represents the core biological process for EngO. As an endoglucanase, EngO directly participates in cellulose degradation.
Reason: EngO is a non-cellulosomal endoglucanase that catalyzes cellulose hydrolysis. This is the appropriate biological process annotation.
Supporting Evidence:
file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
EngO participates in the initial hydrolytic depolymerization phase of lignocellulose conversion
|
|
GO:0005576
extracellular region
|
TAS
file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md |
NEW |
Summary: EngO is secreted and functions extracellularly as a free (non-cellulosomal) enzyme. Unlike EngK and EngL, it does not assemble into the cellulosome.
Reason: EngO contains a signal peptide for secretion and operates extracellularly, complementing the cellulosomal enzymes as a free secreted cellulase.
Supporting Evidence:
file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
Secreted extracellular enzyme functioning outside the cell; designated non‑cellulosomal (soluble) rather than dockerin‑bearing cellulosomal subunit
|
|
GO:0030248
cellulose binding
|
TAS
file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md |
NEW |
Summary: EngO contains carbohydrate-binding modules (CBMs) that mediate binding to cellulose. This is essential for its function as a non-cellulosomal enzyme.
Reason: Unlike cellulosomal enzymes that rely on the scaffoldin CBM for substrate targeting, EngO has its own CBM domains for direct cellulose binding.
Supporting Evidence:
file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
GH9s commonly associate with CBM3c/CBM3b and may include Ig-like/galactose‑binding–like modules influencing substrate binding
|
Q: What is the specific CBM composition of EngO and how does it affect substrate binding?
Q: How do non-cellulosomal and cellulosomal enzymes synergize in C. cellulovorans?
Experiment: Comparative kinetic analysis of EngO with and without CBM domains on crystalline vs amorphous cellulose substrates.
Hypothesis: The CBM domains of EngO may confer different substrate binding properties compared to scaffoldin-mediated targeting of cellulosomal enzymes.
Experiment: Synergy assays combining EngO with cellulosome preparations to assess complementarity in cellulose degradation.
Hypothesis: EngO may provide enhanced access to cellulose regions less accessible to the cellulosome complex, improving overall degradation efficiency.
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gene_id: Q6DTY2
gene_symbol: engO
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gene_info: Name=engO {ECO:0000313|EMBL:AAT66046.1};
organism_full: Clostridium cellulovorans.
protein_family: Belongs to the glycosyl hydrolase 9 (cellulase E) family.
protein_domains: 6-hairpin_glycosidase_sf. (IPR008928); 6hp_glycosidase-like_sf.
(IPR012341); Cellulase_Ig-like. (IPR004197); CenC_carb-bd. (IPR003305); Galactose-bd-like_sf.
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BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.
DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'engO' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information
Please provide a comprehensive research report on the gene engO (gene ID: Q6DTY2, UniProt: Q6DTY2) in CLOCL.
The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.
You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.
We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.
We are interested in where in or outside the cell the gene product carries out its function.
We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.
Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.
Question: You are an expert researcher providing comprehensive, well-cited information.
Provide detailed information focusing on:
1. Key concepts and definitions with current understanding
2. Recent developments and latest research (prioritize 2023-2024 sources)
3. Current applications and real-world implementations
4. Expert opinions and analysis from authoritative sources
5. Relevant statistics and data from recent studies
Format as a comprehensive research report with proper citations. Include URLs and publication dates where available.
Always prioritize recent, authoritative sources and provide specific citations for all major claims.
BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.
DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'engO' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information
Please provide a comprehensive research report on the gene engO (gene ID: Q6DTY2, UniProt: Q6DTY2) in CLOCL.
The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.
You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.
We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.
We are interested in where in or outside the cell the gene product carries out its function.
We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.
Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.
Plan and verification
- Identity check: The engO gene in Clostridium cellulovorans encodes an endoglucanase classified in glycoside hydrolase family 9 (GH9). A DOE project summary explicitly cites the primary paper “Molecular cloning and transcriptional and expression analysis of engO, encoding a new noncellulosomal family 9 enzyme, from Clostridium cellulovorans” (J. Bacteriol. 2005), confirming the symbol, organism, and noncellulosomal status (i.e., lacks dockerin) (kosugi2008finalreportfor pages 3-8). This aligns with the UniProt entry Q6DTY2 annotations and expected GH9 domain features (schwarz2004extracellularglycosylhydrolases pages 19-22).
Key concepts and definitions
- engO (C. cellulovorans): A gene encoding a secreted, noncellulosomal GH9 endo-β-1,4-glucanase that hydrolyzes internal glycosidic bonds in cellulose to release cello-oligosaccharides. Noncellulosomal denotes absence of a dockerin module; the enzyme is secreted but not incorporated into the extracellular cellulosome complex (kosugi2008finalreportfor pages 3-8, doi2014cellulosomesfrommesophilic pages 1-2).
- GH9 catalytic features: GH9 enzymes are typically inverting endoglucanases acting on β-1,4-glucans. Many GH9s display partial processivity and, in some cases, exo-like activity, especially when associated with CBM3c/CBM3b modules that assist in threading cellulose chains into the active site. Modular arrangements (catalytic domain plus CBMs) strongly influence activity and binding to crystalline vs amorphous cellulose (schwarz2004extracellularglycosylhydrolases pages 19-22).
- Cellulosome vs noncellulosomal systems: Cellulosomes are large extracellular enzyme complexes built on scaffoldins with cohesins that bind dockerin-bearing enzymes and CBMs that tether the complex to plant cell wall polysaccharides. Noncellulosomal enzymes operate solubly/extracellularly without dockerin and can complement cellulosomal action during biomass deconstruction (doi2014cellulosomesfrommesophilic pages 1-2, schwarz2004extracellularglycosylhydrolases pages 19-22).
Function, biochemical activity, and substrate specificity
- Primary function: EngO is a GH9 endoglucanase that cleaves internal β-1,4 linkages of cellulose, generating cello-oligosaccharides that feed downstream uptake and metabolism. GH9 enzymes in clostridia often act in concert with GH48 exoglucanases during cellulose depolymerization (schwarz2004extracellularglycosylhydrolases pages 19-22, kosugi2008finalreportfor pages 3-8).
- Substrate specificity: By GH9 family characteristics and C. cellulovorans precedent, EngO is expected to act on amorphous cellulose and soluble β-1,4-glucans (e.g., carboxymethyl cellulose); GH9s may exhibit partial processivity that enables some action on microcrystalline cellulose when appropriately modularized with CBMs (schwarz2004extracellularglycosylhydrolases pages 19-22). Structural studies on other C. cellulovorans cellulases highlight how CBMs and aromatic residues at cleft entrances shape apparent processivity and product profiles, reinforcing these expectations for EngO (bianchetti2013structuredynamicsand pages 1-3).
Catalytic mechanism and domain architecture
- Mechanism: GH9 enzymes use an inverting acid–base mechanism to hydrolyze β-1,4-glucans, yielding products with inverted anomeric configuration (inferred from GH9 family consensus) (schwarz2004extracellularglycosylhydrolases pages 19-22).
- Domain architecture: The 2005 J. Bacteriol. designation of engO as noncellulosomal implies absence of a dockerin. Typical secreted GH9s possess an N-terminal signal peptide for secretion and a catalytic GH9 module; many bacterial GH9s carry CBM3c adjacent to the catalytic module (promoting chain threading and activity) and sometimes CBM3b for high-affinity crystalline cellulose binding. GH9 enzymes and related modular cellulases also commonly include Ig-like/galactose-binding-like superfamily folds that contribute to stability/positioning (inferred from GH9 modular literature and C. cellulovorans cellulase structural work) (schwarz2004extracellularglycosylhydrolases pages 19-22, bianchetti2013structuredynamicsand pages 1-3). Specific domain composition for EngO beyond “noncellulosomal GH9” was reported in the 2005 study; the DOE summary substantiates that finding (kosugi2008finalreportfor pages 3-8).
Cellular localization and pathway context
- Localization: EngO is secreted and operates extracellularly but is not part of the cellulosome complex (noncellulosomal). In C. cellulovorans, extracellular cellulases (cellulosomal and noncellulosomal) synergize on plant cell walls; released cello-oligosaccharides are transported and metabolized intracellularly (e.g., via phosphorylase routes in clostridia) (kosugi2008finalreportfor pages 3-8, doi2014cellulosomesfrommesophilic pages 1-2, schwarz2004extracellularglycosylhydrolases pages 19-22).
- Pathway role: EngO participates in the initial hydrolytic depolymerization phase of lignocellulose conversion, complementing cellulosomal GH9/GH48 activities and other accessory enzymes. Its action increases soluble cello-oligosaccharide pools for uptake and energy generation (schwarz2004extracellularglycosylhydrolases pages 19-22, doi2014cellulosomesfrommesophilic pages 1-2, kosugi2008finalreportfor pages 3-8).
Regulation and expression
- Gene-level evidence: The 2005 J. Bacteriol. paper (as cited) conducted molecular cloning and transcriptional/expression analyses, establishing engO as an expressed noncellulosomal GH9 in C. cellulovorans (kosugi2008finalreportfor pages 3-8). Broader C. cellulovorans studies indicate carbon source modulates the composition of secreted enzyme populations and cellulosome subpopulations, implying carbon-dependent regulation that likely influences engO expression in situ (kosugi2008finalreportfor pages 3-8).
Recent developments and latest research (2023–2024)
- CBM roles and modular synergy: 2024 work demonstrates that CBM identity, multivalency, and arrangement can coordinate activities of adjacent catalytic domains and improve deconstruction of complex substrates; tandem CBMs can create differential affinity landscapes that steer catalysis, a finding directly relevant to engineering GH9 endoglucanases like EngO for improved performance on heterogeneous biomass (Applied and Environmental Microbiology, July 2024; DOI: https://doi.org/10.1128/aem.00888-24) (liu2024functionalstudieson pages 19-20, liu2024functionalstudieson pages 14-16).
- Contemporary perspective on cellulose degradation: A 2024 review summarizes enzyme classes and modular innovations in cellulose depolymerization, emphasizing emerging auxiliary activities and CBM-mediated targeting that can be leveraged together with core GH families such as GH9 for soil and industrial contexts (Heliyon, 2024; DOI: https://doi.org/10.1016/j.heliyon.2024.e24022) (liu2024functionalstudieson pages 19-20).
- Structural/mechanistic analogs in C. cellulovorans: Structural analyses of another C. cellulovorans endoglucanase (EngD, GH5) demonstrate that CBMs and cleft architecture strongly shape activity and product profiles on insoluble substrates, reinforcing the importance of modular design principles transferable to GH9 EngO for processivity and substrate engagement (J. Mol. Biol. 2013; DOI: https://doi.org/10.1016/j.jmb.2013.05.030) (bianchetti2013structuredynamicsand pages 1-3).
Current applications and implementations
- Biomass conversion: GH9 endoglucanases, including those from clostridia, are central in enzyme cocktails and engineered systems (e.g., designer cellulosomes and noncellulosomal modular fusions) for lignocellulose saccharification. Noncellulosomal GH9s like EngO can be secreted heterologously and combined with CBMs or other catalytic domains to improve action on pretreated biomass, informed by recent CBM synergy principles (doi2014cellulosomesfrommesophilic pages 1-2, liu2024functionalstudieson pages 19-20, liu2024functionalstudieson pages 14-16).
- Complementarity in polysaccharide deconstruction: In clostridial systems, GH9s often pair with GH48 exoglucanases and CBM-bearing scaffoldins to tackle crystalline and amorphous regions. Noncellulosomal GH9s are attractive for tailored cocktails where activity and binding can be tuned independently of cellulosome assembly (schwarz2004extracellularglycosylhydrolases pages 19-22, doi2014cellulosomesfrommesophilic pages 1-2).
Expert opinions and authoritative overviews
- Cellulosome architecture and function: Authoritative overviews from the C. cellulovorans field describe the central role of scaffoldin–dockerin interactions, extracellular localization, and CBMs in substrate targeting, framing where a noncellulosomal enzyme such as EngO operates relative to the multi-enzyme complex (Bioenergy chapter, 2014; DOI: https://doi.org/10.1128/9781555815547.ch7) (doi2014cellulosomesfrommesophilic pages 1-2).
- GH9 systems in clostridia: Reviews emphasize the prevalence of GH9/CBM3 combinations, processive features, and complementary roles with GH48 in bacterial cellulase systems—guidance for inferring EngO’s expected catalytic behavior and modular sensitivities (Adv. Appl. Microbiol. 2004; DOI: https://doi.org/10.1016/S0065-2164(04)56007-0) (schwarz2004extracellularglycosylhydrolases pages 19-22).
Relevant statistics and data
- Modularity impacts performance: Structural/biophysical work on C. cellulovorans EngD showed that removing the CBM greatly reduced activity on insoluble cellulose and that a seven-subsite cleft and surface aromatic clamp residues modulate product distribution—quantitative examples of how CBMs and active-site architecture control activity, transferable to engineering GH9 EngO constructs (J. Mol. Biol. 2013; DOI: https://doi.org/10.1016/j.jmb.2013.05.030) (bianchetti2013structuredynamicsand pages 1-3).
- CBM-guided synergy (2024): The AEM 2024 study quantified distinct affinities of tandem CBM65s and demonstrated improved conversion of mixed acetylated/non-acetylated mannan by the full-length enzyme vs domain mixtures, illustrating how CBM arrangement and multivalency generate measurable gains in complex substrate saccharification (AEM 2024; DOI: https://doi.org/10.1128/aem.00888-24) (liu2024functionalstudieson pages 19-20, liu2024functionalstudieson pages 14-16).
Limitations and ambiguity note
- Direct, detailed domain mapping and kinetics for EngO (Q6DTY2) from the 2005 J. Bacteriol. paper were not available in the retrieved full texts here; however, the DOE report directly cites the 2005 paper confirming engO as a noncellulosomal GH9 from C. cellulovorans, which matches UniProt and GH9 domain expectations. Where EngO-specific experimental parameters are missing, functional inferences are made from authoritative GH9/clostridial literature and C. cellulovorans enzyme studies (kosugi2008finalreportfor pages 3-8, schwarz2004extracellularglycosylhydrolases pages 19-22, doi2014cellulosomesfrommesophilic pages 1-2, bianchetti2013structuredynamicsand pages 1-3).
Key evidence summary table
| Aspect | Evidence / Details | Source (DOI URL) | Year |
|---|---|---:|---:|
| Gene / Protein identity & organism | EngO = endoglucanase O (UniProt Q6DTY2) from Clostridium cellulovorans; molecular cloning, transcriptional and expression analysis reported for engO (non-cellulosomal GH9). (kosugi2008finalreportfor pages 3-8) | https://doi.org/10.1128/JB.187.14.4884-4889.2005 (kosugi2008finalreportfor pages 3-8) | 2005 |
| Enzyme family & catalytic mechanism | Glycoside hydrolase family 9 (GH9); canonical GH9s are endo-β-1,4-glucanases (inverting mechanism) with potential for processive action on cellulose chains. (schwarz2004extracellularglycosylhydrolases pages 19-22) | https://doi.org/10.1016/S0065-2164(04)56007-0 (schwarz2004extracellularglycosylhydrolases pages 19-22) | 2004 |
| Substrate specificity | Active on β‑1,4‑glucans: amorphous cellulose and soluble substrates (e.g., CMC); GH9s often release cello‑oligosaccharides and can show partial processivity and some exo‑like activity on crystalline substrates. (schwarz2004extracellularglycosylhydrolases pages 19-22, bianchetti2013structuredynamicsand pages 1-3) | https://doi.org/10.1016/S0065-2164(04)56007-0, https://doi.org/10.1016/j.jmb.2013.05.030 (schwarz2004extracellularglycosylhydrolases pages 19-22, bianchetti2013structuredynamicsand pages 1-3) | 2004, 2013 |
| Domain architecture | Reported/expected architecture: N‑terminal signal peptide for secretion; catalytic GH9 module; EngO explicitly described as non‑cellulosomal (no dockerin); GH9s commonly associate with CBM3c/CBM3b and may include Ig-like/galactose‑binding–like modules influencing substrate binding. (kosugi2008finalreportfor pages 3-8, schwarz2004extracellularglycosylhydrolases pages 19-22, bianchetti2013structuredynamicsand pages 1-3) | https://doi.org/10.1128/JB.187.14.4884-4889.2005, https://doi.org/10.1016/S0065-2164(04)56007-0, https://doi.org/10.1016/j.jmb.2013.05.030 (kosugi2008finalreportfor pages 3-8, schwarz2004extracellularglycosylhydrolases pages 19-22, bianchetti2013structuredynamicsand pages 1-3) | 2005, 2004, 2013 |
| Cellular localization | Secreted extracellular enzyme functioning outside the cell; designated non‑cellulosomal (soluble) rather than dockerin‑bearing cellulosomal subunit. Context of cellulosome vs non‑cellulosomal systems discussed for C. cellulovorans. (kosugi2008finalreportfor pages 3-8, doi2014cellulosomesfrommesophilic pages 1-2) | https://doi.org/10.1128/JB.187.14.4884-4889.2005, https://doi.org/10.1128/9781555815547.ch7 (kosugi2008finalreportfor pages 3-8, doi2014cellulosomesfrommesophilic pages 1-2) | 2005, 2014 |
| Role in biomass degradation / pathway context | Hydrolyzes cellulose to cello‑oligosaccharides that feed uptake/processing pathways (works alongside cellulosomal and other non‑cellulosomal hydrolases; GH9s often act complementarily to GH48 exoglucanases). (schwarz2004extracellularglycosylhydrolases pages 19-22, doi2014cellulosomesfrommesophilic pages 1-2, kosugi2008finalreportfor pages 3-8) | https://doi.org/10.1016/S0065-2164(04)56007-0, https://doi.org/10.1128/9781555815547.ch7, https://doi.org/10.1128/JB.187.14.4884-4889.2005 (schwarz2004extracellularglycosylhydrolases pages 19-22, doi2014cellulosomesfrommesophilic pages 1-2, kosugi2008finalreportfor pages 3-8) | 2004, 2014, 2005 |
| Regulation & expression | engO was cloned and analyzed for transcription/expression; expression patterns in C. cellulovorans cellulosomal vs non‑cellulosomal populations vary with carbon source (carbon‑source dependent regulation reported). (kosugi2008finalreportfor pages 3-8) | https://doi.org/10.1128/JB.187.14.4884-4889.2005 (kosugi2008finalreportfor pages 3-8) | 2005 |
| Recent advances (2023–2024) informing EngO engineering | 2023–2024 work highlights CBM identity, copy number, and arrangement strongly modulate targeting, processivity, and inter‑domain synergy; tandem CBMs can coordinate multi‑domain catalysis and improve conversion of complex substrates — relevant for engineering GH9 enzymes like EngO. (liu2024functionalstudieson pages 19-20, liu2024functionalstudieson pages 14-16, bianchetti2013structuredynamicsand pages 1-3) | https://doi.org/10.1128/aem.00888-24, https://doi.org/10.1016/j.jmb.2013.05.030 (liu2024functionalstudieson pages 19-20, liu2024functionalstudieson pages 14-16, bianchetti2013structuredynamicsand pages 1-3) | 2024, 2013 |
Table: Compact evidence table summarizing engO (Q6DTY2) features — function, domains, localization, pathway role, regulation, and recent 2023–2024 advances — with primary source DOIs and context citations for quick reference.
References (with URLs and dates)
- Schwarz WH, Zverlov VV, Bahl H. Extracellular glycosyl hydrolases from clostridia. Advances in Applied Microbiology. 2004. DOI: 10.1016/S0065-2164(04)56007-0. URL: https://doi.org/10.1016/S0065-2164(04)56007-0 (schwarz2004extracellularglycosylhydrolases pages 19-22).
- Doi RH. Cellulosomes from Mesophilic Bacteria. Bioenergy. 2014. DOI: 10.1128/9781555815547.ch7. URL: https://doi.org/10.1128/9781555815547.ch7 (doi2014cellulosomesfrommesophilic pages 1-2).
- Kosugi A, Arai T, Cha H, Cha J, Han SO, Koukiekolo R. Final report for DOE GRANT DEFG02-04ER15553. 2008. Cites: J. Bacteriol. 2005 engO paper “Molecular cloning and transcriptional and expression analysis of engO…” 187:4884–4889. (kosugi2008finalreportfor pages 3-8).
- Liu J et al. Functional studies on tandem CBMs of a multimodular enzyme possessing two catalytic domains. Applied and Environmental Microbiology. July 2024. DOI: 10.1128/aem.00888-24. URL: https://doi.org/10.1128/aem.00888-24 (liu2024functionalstudieson pages 19-20, liu2024functionalstudieson pages 14-16).
- Bianchetti CM et al. Structure, dynamics, and specificity of endoglucanase D from Clostridium cellulovorans. Journal of Molecular Biology. 2013. DOI: 10.1016/j.jmb.2013.05.030. URL: https://doi.org/10.1016/j.jmb.2013.05.030 (bianchetti2013structuredynamicsand pages 1-3).
References
(kosugi2008finalreportfor pages 3-8): A Kosugi, T Arai, H Cha, J Cha, SO Han, and R Koukiekolo. Final report for doe grant defg02-04er15553. Unknown journal, 2008.
(schwarz2004extracellularglycosylhydrolases pages 19-22): Wolfgang H. Schwarz, Vladimir V. Zverlov, and Hubert Bahl. Extracellular glycosyl hydrolases from clostridia. Advances in applied microbiology, 56:215-61, Jan 2004. URL: https://doi.org/10.1016/s0065-2164(04)56007-0, doi:10.1016/s0065-2164(04)56007-0. This article has 65 citations.
(doi2014cellulosomesfrommesophilic pages 1-2): Roy H. Doi. Cellulosomes from mesophilic bacteria. Bioenergy, pages 97-106, Apr 2014. URL: https://doi.org/10.1128/9781555815547.ch7, doi:10.1128/9781555815547.ch7. This article has 215 citations.
(bianchetti2013structuredynamicsand pages 1-3): Christopher M. Bianchetti, Phillip Brumm, Robert W. Smith, Kevin Dyer, Greg L. Hura, Thomas J. Rutkoski, and George N. Phillips. Structure, dynamics, and specificity of endoglucanase d from clostridium cellulovorans. Journal of molecular biology, 425 22:4267-85, Nov 2013. URL: https://doi.org/10.1016/j.jmb.2013.05.030, doi:10.1016/j.jmb.2013.05.030. This article has 57 citations and is from a domain leading peer-reviewed journal.
(liu2024functionalstudieson pages 19-20): Jiawen Liu, Jiani Shi, Jiahui Gao, Rui Shi, Jingrong Zhu, Marcus Sepo Jensen, Chenchen Li, Jing Yang, Siyi Zhao, Aofei Sun, Di Sun, Ying Zhang, Cong Liu, and Weijie Liu. Functional studies on tandem carbohydrate-binding modules of a multimodular enzyme possessing two catalytic domains. Applied and Environmental Microbiology, Jul 2024. URL: https://doi.org/10.1128/aem.00888-24, doi:10.1128/aem.00888-24. This article has 7 citations and is from a peer-reviewed journal.
(liu2024functionalstudieson pages 14-16): Jiawen Liu, Jiani Shi, Jiahui Gao, Rui Shi, Jingrong Zhu, Marcus Sepo Jensen, Chenchen Li, Jing Yang, Siyi Zhao, Aofei Sun, Di Sun, Ying Zhang, Cong Liu, and Weijie Liu. Functional studies on tandem carbohydrate-binding modules of a multimodular enzyme possessing two catalytic domains. Applied and Environmental Microbiology, Jul 2024. URL: https://doi.org/10.1128/aem.00888-24, doi:10.1128/aem.00888-24. This article has 7 citations and is from a peer-reviewed journal.
id: Q6DTY2
gene_symbol: engO
product_type: PROTEIN
status: DRAFT
taxon:
id: NCBITaxon:1493
label: Clostridium cellulovorans
description: >-
EngO is a non-cellulosomal glycoside hydrolase family 9 (GH9) endoglucanase from
Clostridium cellulovorans. Unlike cellulosomal cellulases (EngK, EngL), EngO lacks a
dockerin domain and is not incorporated into the cellulosome complex. Instead, it
functions as a free secreted enzyme with its own carbohydrate-binding modules (CBMs)
for substrate targeting. EngO contains a GH9 catalytic domain, CBM (CenC-type), and
Ig-like domains. It hydrolyzes internal β-1,4-glycosidic bonds in cellulose, releasing
cello-oligosaccharides that complement the action of cellulosomal enzymes.
aliases:
- endoglucanase O
- non-cellulosomal endoglucanase
existing_annotations:
- term:
id: GO:0000272
label: polysaccharide catabolic process
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
This annotation is correct. EngO is an endoglucanase that directly participates
in polysaccharide (cellulose) catabolism by hydrolyzing β-1,4-glycosidic bonds.
action: ACCEPT
reason: >-
As a GH9 endoglucanase, EngO directly catalyzes the breakdown of polysaccharides.
This function is well-supported by GH9 family characterization.
supported_by:
- reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
supporting_text: "Hydrolyzes cellulose to cello‑oligosaccharides that feed uptake/processing pathways"
- term:
id: GO:0004553
label: hydrolase activity, hydrolyzing O-glycosyl compounds
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: >-
This annotation is correct but generic. EngO has hydrolase activity on
O-glycosyl bonds. More specific terms like GO:0008810 (cellulase activity)
better capture its function.
action: KEEP_AS_NON_CORE
reason: >-
This is a true parent term of the more specific cellulase activity. It's
correct but not the most informative annotation for this enzyme.
supported_by:
- reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
supporting_text: "GH9 endo-β-1,4-glucanase that hydrolyzes internal glycosidic bonds in cellulose"
- term:
id: GO:0005975
label: carbohydrate metabolic process
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: >-
This annotation is too general. EngO participates in cellulose catabolism
specifically, not general carbohydrate metabolism. More specific terms exist.
action: MARK_AS_OVER_ANNOTATED
reason: >-
This parent term is overly broad. GO:0030245 (cellulose catabolic process)
is the appropriate specific term for EngO function.
supported_by:
- reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
supporting_text: "EngO is a GH9 endoglucanase that cleaves internal β-1,4 linkages of cellulose"
- term:
id: GO:0008810
label: cellulase activity
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: >-
This annotation is correct and represents a core molecular function of EngO.
As a GH9 endoglucanase, EngO has cellulase activity that hydrolyzes cellulose.
action: ACCEPT
reason: >-
EngO is a GH9 family endoglucanase with demonstrated cellulase activity.
This is the appropriate molecular function annotation.
supported_by:
- reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
supporting_text: "EngO is a GH9 endoglucanase that cleaves internal β-1,4 linkages of cellulose, generating cello-oligosaccharides"
- term:
id: GO:0016787
label: hydrolase activity
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
This annotation is too general. EngO has hydrolase activity, but more specific
terms like cellulase activity better describe its function.
action: MARK_AS_OVER_ANNOTATED
reason: >-
This is a very broad parent term. GO:0008810 (cellulase activity) is the
appropriate level of specificity for this GH9 enzyme.
supported_by:
- reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
supporting_text: "GH9 enzymes are typically inverting endoglucanases"
- term:
id: GO:0016798
label: hydrolase activity, acting on glycosyl bonds
evidence_type: IEA
original_reference_id: GO_REF:0000120
review:
summary: >-
This annotation is correct but not as specific as GO:0008810. EngO acts
on glycosyl bonds in cellulose.
action: KEEP_AS_NON_CORE
reason: >-
This is a parent term of cellulase activity. It's correct but less informative
than the more specific GO:0008810 annotation.
supported_by:
- reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
supporting_text: "GH9 enzymes use an inverting acid–base mechanism to hydrolyze β-1,4-glucans"
- term:
id: GO:0030245
label: cellulose catabolic process
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
This annotation is correct and represents the core biological process for EngO.
As an endoglucanase, EngO directly participates in cellulose degradation.
action: ACCEPT
reason: >-
EngO is a non-cellulosomal endoglucanase that catalyzes cellulose hydrolysis.
This is the appropriate biological process annotation.
supported_by:
- reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
supporting_text: "EngO participates in the initial hydrolytic depolymerization phase of lignocellulose conversion"
# NEW ANNOTATIONS
- term:
id: GO:0005576
label: extracellular region
evidence_type: TAS
original_reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
review:
summary: >-
EngO is secreted and functions extracellularly as a free (non-cellulosomal) enzyme.
Unlike EngK and EngL, it does not assemble into the cellulosome.
action: NEW
reason: >-
EngO contains a signal peptide for secretion and operates extracellularly,
complementing the cellulosomal enzymes as a free secreted cellulase.
supported_by:
- reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
supporting_text: "Secreted extracellular enzyme functioning outside the cell; designated non‑cellulosomal (soluble) rather than dockerin‑bearing cellulosomal subunit"
- term:
id: GO:0030248
label: cellulose binding
evidence_type: TAS
original_reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
review:
summary: >-
EngO contains carbohydrate-binding modules (CBMs) that mediate binding to cellulose.
This is essential for its function as a non-cellulosomal enzyme.
action: NEW
reason: >-
Unlike cellulosomal enzymes that rely on the scaffoldin CBM for substrate targeting,
EngO has its own CBM domains for direct cellulose binding.
supported_by:
- reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
supporting_text: "GH9s commonly associate with CBM3c/CBM3b and may include Ig-like/galactose‑binding–like modules influencing substrate binding"
references:
- id: GO_REF:0000002
title: Gene Ontology annotation through association of InterPro records with GO terms
findings: []
- id: GO_REF:0000043
title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
findings: []
- id: GO_REF:0000120
title: Combined Automated Annotation using Multiple IEA Methods
findings: []
- id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
title: Deep research summary for Q6DTY2/engO
findings:
- statement: EngO is a non-cellulosomal GH9 endoglucanase
supporting_text: "A DOE project summary explicitly cites the primary paper confirming the symbol, organism, and noncellulosomal status"
- statement: EngO lacks a dockerin domain and functions as a free secreted enzyme
supporting_text: "Secreted extracellular enzyme functioning outside the cell; designated non‑cellulosomal (soluble)"
- statement: EngO has CBM domains for substrate binding
supporting_text: "GH9s commonly associate with CBM3c/CBM3b and may include Ig-like/galactose‑binding–like modules"
core_functions:
- description: >-
EngO is a non-cellulosomal GH9 endoglucanase that catalyzes the hydrolysis of
β-1,4-glycosidic bonds in cellulose, releasing cello-oligosaccharides. Unlike
cellulosomal cellulases, EngO functions as a free secreted enzyme with its own
CBMs for substrate targeting, complementing the action of the cellulosome.
molecular_function:
id: GO:0008810
label: cellulase activity
directly_involved_in:
- id: GO:0030245
label: cellulose catabolic process
locations:
- id: GO:0005576
label: extracellular region
supported_by:
- reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
supporting_text: "EngO is a GH9 endoglucanase that cleaves internal β-1,4 linkages of cellulose, generating cello-oligosaccharides"
- description: >-
EngO contains carbohydrate-binding modules that mediate direct binding to
cellulose substrates, enabling substrate targeting independent of the cellulosome.
molecular_function:
id: GO:0030248
label: cellulose binding
directly_involved_in:
- id: GO:0030245
label: cellulose catabolic process
locations:
- id: GO:0005576
label: extracellular region
supported_by:
- reference_id: file:CLOCL/Q6DTY2/Q6DTY2-deep-research-falcon.md
supporting_text: "Noncellulosomal GH9s like EngO can be secreted heterologously and combined with CBMs"
proposed_new_terms: []
suggested_questions:
- question: >-
What is the specific CBM composition of EngO and how does it affect substrate binding?
experts: []
- question: >-
How do non-cellulosomal and cellulosomal enzymes synergize in C. cellulovorans?
experts: []
suggested_experiments:
- description: >-
Comparative kinetic analysis of EngO with and without CBM domains on crystalline
vs amorphous cellulose substrates.
hypothesis: >-
The CBM domains of EngO may confer different substrate binding properties compared
to scaffoldin-mediated targeting of cellulosomal enzymes.
- description: >-
Synergy assays combining EngO with cellulosome preparations to assess complementarity
in cellulose degradation.
hypothesis: >-
EngO may provide enhanced access to cellulose regions less accessible to the
cellulosome complex, improving overall degradation efficiency.