EngL is a glycoside hydrolase family 9 (GH9) endoglucanase from the Clostridium cellulovorans cellulosome. It contains a GH9 catalytic domain and a C-terminal type I dockerin domain for cellulosome assembly. Unlike non-cellulosomal cellulases (e.g., EngD), EngL lacks an intrinsic carbohydrate-binding module and relies on dockerin-mediated incorporation into the CbpA scaffoldin for cellulose targeting. EngL functions as an endo-β-1,4-glucanase that hydrolyzes internal β-1,4 linkages in cellulose.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000272 polysaccharide catabolic process | IEA GO_REF:0000120 | ACCEPT | Summary: This annotation is correct. EngL is an endoglucanase that directly participates in polysaccharide (cellulose) catabolism by hydrolyzing β-1,4-glycosidic bonds. Reason: As a GH9 endoglucanase, EngL directly catalyzes the breakdown of polysaccharides. This is a core function supported by biochemical characterization. Supporting Evidence: file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md Endo‑β‑1,4‑glucanase acting on cellulose/CMC; within cellulosomes GH9s often exhibit processive behavior aiding crystalline cellulose degradation |
| GO:0004553 hydrolase activity, hydrolyzing O-glycosyl compounds | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: This annotation is correct but generic. EngL 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/Q9RGE6/Q9RGE6-deep-research-falcon.md EngL conforms to a GH9 endoglucanase with a C‑terminal dockerin |
| GO:0005975 carbohydrate metabolic process | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: This annotation is too general. EngL 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 EngL function. Supporting Evidence: file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md EngL is an endo‑β‑1,4‑glucanase that hydrolyzes internal β‑1,4 linkages in cellulose |
| GO:0016787 hydrolase activity | IEA GO_REF:0000043 | MARK AS OVER ANNOTATED | Summary: This annotation is too general. EngL 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/Q9RGE6/Q9RGE6-deep-research-falcon.md GH9 enzymes in cellulosomes often display endo‑processivity |
| GO:0016798 hydrolase activity, acting on glycosyl bonds | IEA GO_REF:0000043 | KEEP AS NON CORE | Summary: This annotation is correct but not as specific as GO:0008810. EngL 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/Q9RGE6/Q9RGE6-deep-research-falcon.md EngL conforms to a GH9 endoglucanase |
| GO:0008810 cellulase activity | TAS file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md | NEW | Summary: EngL is a GH9 endoglucanase with cellulase activity. This is the appropriate molecular function annotation for this enzyme. Reason: EngL is classified in GH9 family and functions as an endo-β-1,4-glucanase acting on cellulose substrates. Supporting Evidence: file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md By family assignment and organismal context, EngL is an endo‑β‑1,4‑glucanase that hydrolyzes internal β‑1,4 linkages in cellulose and soluble cellulose analogs |
| GO:0030245 cellulose catabolic process | TAS file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md | NEW | Summary: EngL directly participates in cellulose degradation as a cellulosomal endoglucanase. Reason: As a GH9 cellulosomal enzyme, EngL contributes to the degradation of plant cell wall cellulose. Supporting Evidence: file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md EngL contributes catalytic activity within the cellulosome to deconstruct plant cell walls |
| GO:0043263 cellulosome | TAS file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md | NEW | Summary: EngL is a cellulosomal enzyme that assembles into the cellulosome via its dockerin domain. This cellular component annotation is essential. Reason: EngL contains a type I dockerin domain and is incorporated into the CbpA-based cellulosome complex. Supporting Evidence: file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md Secreted/extracellular and incorporated into the cellulosome via dockerin→cohesin binding to scaffoldin CbpA |
| GO:0005576 extracellular region | TAS file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md | NEW | Summary: EngL is secreted and functions extracellularly as part of the cellulosome. Reason: EngL is secreted and assembles into extracellular cellulosome complexes via its dockerin domain binding to CbpA cohesins. Supporting Evidence: file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md Secreted, extracellular cellulosome-associated via dockerin–cohesin binding to CbpA |
| GO:1990311 type-I cohesin domain binding | TAS file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md | NEW | Summary: EngL contains a type I dockerin domain that binds to type I cohesins on the CbpA scaffoldin, enabling cellulosome assembly. Reason: The dockerin domain mediates binding to cohesin domains, which is essential for cellulosome incorporation. Supporting Evidence: file:CLOCL/Q9RGE6/Q9RGE6-deep-research-falcon.md Typical architecture: GH9 catalytic domain + C-terminal dockerin (marks cellulosome incorporation) |
| GO:0044575 cellulosome assembly | NAS | NEW | Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations. |
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Download this section (compressed HTML)Q: What are the kinetic parameters of EngL on different cellulose substrates?
Q: How does EngL's activity compare to EngK within the cellulosome complex?
Experiment: Detailed kinetic characterization of EngL on crystalline and amorphous cellulose substrates to determine Km, kcat, and processivity.
Hypothesis: EngL may exhibit processive behavior characteristic of some GH9 enzymes when part of the cellulosome complex.
Experiment: Synergy assays with EngL and other cellulosomal enzymes (EngK, ExgS) on crystalline cellulose.
Hypothesis: EngL provides complementary endo-activity that synergizes with exoglucanases for efficient cellulose degradation.
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