Small ribosomal subunit protein uS4 (30S ribosomal protein S4) of Pseudomonas aeruginosa PAO1. uS4 is a primary 16S rRNA-binding protein that nucleates early assembly of the 30S ribosomal subunit body. It binds directly to 16S rRNA, inducing conformational rearrangements required for recruitment of secondary and tertiary binding proteins. In the mature 30S subunit, uS4 contributes to translational accuracy through its interface with uS5; disruption of this interface during tRNA selection controls the transition between open and closed conformations of the decoding center. The protein belongs to the universal ribosomal protein uS4 family and contains an N-terminal domain and a C-terminal S4 RNA-binding domain.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
|
GO:0003735
structural constituent of ribosome
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: IBA annotation inferred from phylogenetic analysis (PANTHER). uS4 is a stable, stoichiometric component of the 30S ribosomal subunit whose primary molecular function is to provide structural integrity to the particle. It binds directly to 16S rRNA and is essential for 30S assembly and stability. The BioReason SFT functional summary (rpsD-deep-research-bioreason-sft.md) correctly identifies uS4 as a structural organizer of the small subunit.
Reason: uS4 is unambiguously a structural constituent of the ribosome. It is one of the primary binding proteins of the 30S subunit and remains stably incorporated throughout the translation cycle. Multiple cryo-EM structures confirm its integral position in the 30S subunit.
Supporting Evidence:
PMID:28483689
ribosomal protein uS4 helps initiate the assembly of the small subunit by binding directly to 16S rRNA
|
|
GO:0015935
small ribosomal subunit
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: IBA annotation for cellular component localization to the small ribosomal subunit. uS4 is a core component of the bacterial 30S subunit confirmed by multiple cryo-EM structures of the P. aeruginosa 70S ribosome (PDB 7UNR, 7UNV, 7UNW, 8RWG).
Reason: uS4 is resolved in multiple cryo-EM structures of the P. aeruginosa 70S ribosome at 2.5-2.9 A resolution, confirming its stable incorporation into the 30S subunit.
Supporting Evidence:
PMID:28483689
ribosomal protein uS4 helps initiate the assembly of the small subunit by binding directly to 16S rRNA
|
|
GO:0019843
rRNA binding
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: IBA annotation for rRNA binding. uS4 is one of the primary rRNA binding proteins of the 30S subunit, binding directly to the 16S rRNA where it nucleates assembly of the subunit body.
Reason: rRNA binding is the central molecular function of uS4. It binds 16S rRNA directly and is one of the first proteins to associate with the rRNA during in vitro 30S reconstitution. This has been extensively characterized in E. coli and is conserved across bacteria.
Supporting Evidence:
PMID:17376481
Additionally, a temperature-dependent conformational rearrangement was reported for a complex of primary r-protein S4 and 16 S rRNA
PMID:28483689
ribosomal protein uS4 helps initiate the assembly of the small subunit by binding directly to 16S rRNA
|
|
GO:0042274
ribosomal small subunit biogenesis
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: IBA annotation for ribosomal small subunit biogenesis. uS4 is a primary binding protein that initiates the 30S assembly pathway by binding 16S rRNA and inducing conformational changes that enable recruitment of downstream assembly proteins.
Reason: uS4 is essential for 30S biogenesis as one of the primary binding proteins that nucleates assembly. Temperature-dependent conformational rearrangements of the S4-16S rRNA complex are required for downstream assembly events. C-terminal truncations of uS4 cause assembly defects.
Supporting Evidence:
PMID:17376481
Some of the architectures achieved in these rearrangements are consistent with subsequent downstream assembly events such as assembly of the secondary and tertiary binding r-proteins
PMID:28483689
the C-terminal requirements for ribosome assembly are less rigid than for mRNA decoding
|
|
GO:0003723
RNA binding
|
IEA
GO_REF:0000002 |
KEEP AS NON CORE |
Summary: IEA annotation from InterPro2GO mapping (IPR002942 S4 RNA-binding domain and IPR036986 S4 RNA-binding domain superfamily). RNA binding is correct but less specific than rRNA binding (GO:0019843) which is already annotated.
Reason: The S4 RNA-binding domain does indeed confer RNA binding activity. However, the more specific rRNA binding (GO:0019843) is already annotated via IBA and IEA evidence. This general RNA binding annotation is redundant with the more specific term but not incorrect; uS4 also has mRNA binding activity as a translational autorepressor in E. coli.
|
|
GO:0003735
structural constituent of ribosome
|
IEA
GO_REF:0000002 |
ACCEPT |
Summary: IEA annotation from InterPro2GO mapping (IPR005709 bacterial uS4 family). This duplicates the IBA annotation for the same term.
Reason: Correct InterPro2GO mapping. The bacterial uS4 family (IPR005709) appropriately maps to structural constituent of ribosome. Consistent with the IBA annotation above.
|
|
GO:0006412
translation
|
IEA
GO_REF:0000120 |
ACCEPT |
Summary: IEA annotation from combined automated methods (UniRule/InterPro). uS4 is an essential structural component of the 30S subunit required for translation.
Reason: As a core 30S ribosomal protein, uS4 is directly involved in translation. The mature 30S subunit containing uS4 participates in mRNA decoding, and uS4 specifically contributes to translational accuracy via its interaction with uS5 at the decoding center.
Supporting Evidence:
PMID:25548247
Ribosomal proteins S4 and S5 participate in the decoding and assembly processes on the ribosome
|
|
GO:0015935
small ribosomal subunit
|
IEA
GO_REF:0000002 |
ACCEPT |
Summary: IEA annotation from InterPro2GO mapping (IPR005709). Duplicates the IBA annotation for the same cellular component.
Reason: Correct InterPro2GO mapping consistent with all structural and biochemical evidence for 30S subunit localization.
|
|
GO:0019843
rRNA binding
|
IEA
GO_REF:0000120 |
ACCEPT |
Summary: IEA annotation from combined automated methods (UniRule mapping from IPR001912, IPR018079, IPR022801). Duplicates the IBA annotation for the same molecular function.
Reason: Correct automated annotation. Multiple InterPro signatures for uS4 domains all point to rRNA binding as the core molecular function.
|
|
GO:0022627
cytosolic small ribosomal subunit
|
NAS
PMID:28483689 The C-terminus of ribosomal protein uS4 contributes to small... |
NEW |
Summary: uS4 is a stable component of the bacterial cytosolic 30S ribosomal subunit. This is more specific than GO:0015935 (small ribosomal subunit) and accurately reflects that bacterial ribosomes are cytosolic. The BioReason SFT trace (rpsD-deep-research-bioreason-sft.md) also correctly infers cytosolic small ribosomal subunit localization.
Reason: The existing annotations use GO:0015935 (small ribosomal subunit) which is correct but does not specify the cytosolic compartment. Since P. aeruginosa ribosomes are cytosolic, this more specific CC term is warranted.
Supporting Evidence:
PMID:28483689
ribosomal protein uS4 helps initiate the assembly of the small subunit by binding directly to 16S rRNA
file:PSEAE/rpsD/rpsD-deep-research-bioreason-sft.md
[BioReason inferred] cytosolic small ribosomal subunit (GO:0022627)
|
I begin with the InterPro architecture. The sequence is covered almost entirely by bacterial uS4 family signatures: IPR005709 (Small ribosomal subunit protein uS4, bacteria, residues 1–206) spans the full length, with a refined bacterial family call IPR005709 [3–206] and a core family IPR022801 (Small ribosomal subunit protein uS4, residues 7–152). The N-terminus is demarcated by IPR001912 (uS4, N-terminal domain, residues 3–95), followed by a conserved site IPR018079 (uS4 conserved site, residues 94–118) that sits at the junction between the N-terminal region and the canonical RNA-binding core. The central-to-C-terminal half is defined by the S4 RNA-binding fold: IPR036986 (RNA-binding S4 domain superfamily, residues 95–191) and its specific instances IPR002942 (RNA-binding S4 domain, residues 96–160) and IPR002942 (RNA-binding S4 domain, residues 97–143). This ordered layout—an N-terminal module leading into a conserved site and then a compact S4 RNA-binding fold—creates a basic, positively charged surface optimized to recognize and stabilize structured rRNA.
This architecture causes high-affinity binding to the bacterial 16S rRNA, particularly the 3′ major domain. The S4 fold clamps helical junctions and phosphate backbones, while the N-terminal region positions the protein on the platform of the small subunit. The conserved site at residues 94–118 likely contributes key contact residues that nucleate assembly on the rRNA scaffold. Consequently, the molecular function is rRNA binding (GO:0019843), with specificity for 16S rRNA.
By binding and stabilizing the 16S rRNA, uS4 seeds construction of the 30S particle. Its RNA-binding surface organizes early assembly intermediates and recruits additional small-subunit proteins, driving ribosomal small subunit assembly (GO:0000028). Once assembled, the mature 30S engages mRNA and tRNA to execute decoding; uS4, anchored on the platform, helps maintain the geometry of the mRNA channel and the rRNA framework, thereby contributing directly to translation (GO:0006412).
The absence of transmembrane segments and the ribosomal identity place the protein in the cytoplasm, where bacterial ribosomes reside. More specifically, its stable incorporation into the small subunit defines the cellular component as the cytosolic small ribosomal subunit (GO:0022627), consistent with a cytoplasmic localization.
Mechanistically, uS4 binds the 16S rRNA early, stabilizes helix junctions, and creates docking surfaces for other 30S proteins such as S2, S10, S13, and S17. During subunit joining and initiation, its position near the intersubunit interface brings it into transient proximity with large-subunit proteins, explaining functional contacts with L10, L17, L18, L20, L24, and L36. These interactions likely reflect assembly checkpoints and initiation-state contacts rather than permanent binary complexes, with uS4 acting as a structural organizer that ensures accurate 30S architecture and efficient translation initiation.
## Functional Summary
A cytoplasmic small-subunit ribosomal protein that binds 16S rRNA to nucleate and stabilize early steps of 30S assembly on the platform, then remains as a structural organizer during translation. Its basic RNA-binding fold grips structured rRNA elements to shape the small-subunit architecture, recruit additional proteins, and maintain the geometry of the decoding environment, thereby supporting accurate and efficient protein synthesis.
## UniProt Summary
One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the platform of the 30S subunit.
## InterPro Domains
- IPR005709: Small ribosomal subunit protein uS4, bacteria (family) [1-206]
- IPR001912: Small ribosomal subunit protein uS4, N-terminal (domain) [3-95]
- IPR005709: Small ribosomal subunit protein uS4, bacteria (family) [3-206]
- IPR022801: Small ribosomal subunit protein uS4 (family) [7-152]
- IPR018079: Small ribosomal subunit protein uS4, conserved site (conserved_site) [94-118]
- IPR036986: RNA-binding S4 domain superfamily (homologous_superfamily) [95-191]
- IPR002942: RNA-binding S4 domain (domain) [96-160]
- IPR002942: RNA-binding S4 domain (domain) [97-143]
## GO Term Predictions
### Molecular Function
### Biological Process
### Cellular Component
Gene: rpsD (PA4239)
Protein: Small ribosomal subunit protein uS4 (30S ribosomal protein S4)
UniProt: O52759
Organism: Pseudomonas aeruginosa PAO1
The rpsD gene of P. aeruginosa PAO1 was identified through the complete genome sequencing project [PMID:10984043, "Complete genome sequence of Pseudomonas aeruginosa PAO1, an opportunistic pathogen"]. The gene is designated PA4239 in the PAO1 genome.
uS4 is a primary rRNA-binding protein of the bacterial 30S ribosomal subunit. According to PubMed, the UniProt record (HAMAP-Rule:MF_01306) states: "One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the body of the 30S subunit." It also states: "With S5 and S12 plays an important role in translational accuracy."
uS4 is one of the primary binding proteins that initiates 30S ribosomal subunit assembly by binding directly to 16S rRNA. Based on articles retrieved from PubMed, Dutca et al. (2007) demonstrated that the complex of primary r-protein S4 and 16S rRNA undergoes a temperature-dependent conformational rearrangement, showing that S4 actively remodels the rRNA during early assembly: "a temperature-dependent conformational rearrangement was reported for a complex of primary r-protein S4 and 16S rRNA" [PMID:17376481, DOI:10.1016/j.jmb.2007.02.064]. These conformational changes in 16S rRNA are "consistent with subsequent downstream assembly events such as assembly of the secondary and tertiary binding r-proteins" PMID:17376481.
uS4 plays a central role in translational accuracy through its interaction with uS5 at the S4-S5 interface. According to PubMed, Agarwal et al. (2015) showed: "Ribosomal proteins S4 and S5 participate in the decoding and assembly processes on the ribosome and the interaction with specific antibiotic inhibitors of translation. Many of the characterized mutations affecting these proteins decrease the accuracy of translation, leading to a ribosomal-ambiguity phenotype" [PMID:25548247, DOI:10.1128/JB.02485-14]. The same study reported that "the tRNA selection pathway involves a transition between the closed and open conformations of the 30S ribosomal subunit and requires disruption of the interface between the S4 and S5 proteins" PMID:25548247.
Kamath et al. (2017) further characterized the C-terminus of uS4: "uS4 helps initiate the assembly of the small subunit by binding directly to 16S rRNA and at least some of the uS4 alterations that promote miscoding also display assembly defects" and "uS4 is also a translational repressor and is involved in transcription antitermination activities" [PMID:28483689, DOI:10.1016/j.biochi.2017.05.004]. This paper also showed that "the C-terminal requirements for ribosome assembly are less rigid than for mRNA decoding" PMID:28483689.
The P. aeruginosa uS4 protein (206 aa) has been resolved in multiple cryo-EM structures of the P. aeruginosa 70S ribosome:
PDB 7UNR/7UNU/7UNV/7UNW: 70S ribosome initiation complex bound to IF2-GDP/GDPCP [PMID:35697706, DOI:10.1038/s41467-022-31129-2]. These structures from Basu et al. (2022) show the complete P. aeruginosa 70S ribosome including uS4 at 2.6-2.9 A resolution.
PDB 8RWG: Additional P. aeruginosa ribosome structure at 2.46 A resolution.
Halfon et al. (2019) solved the structure of P. aeruginosa ribosomes from a clinical isolate, including the 30S subunit (PDB 6SPE) [PMID:31611393, DOI:10.1073/pnas.1909831116].
The protein contains:
- N-terminal domain (IPR001912, residues 3-95): uS4 N-terminal domain
- Conserved site (IPR018079, residues 94-118): uS4 conserved site at the junction between N-terminal and RNA-binding domains
- S4 RNA-binding domain (IPR002942, residues 96-160): canonical S4 fold for RNA recognition
- Bacterial uS4 family (IPR005709): full-length bacterial S4 family signature
While not directly demonstrated in P. aeruginosa, E. coli S4 has additional established functions:
- Translational autoregulation: S4 represses translation of its own mRNA and the alpha operon mRNA PMID:28483689
- Transcription antitermination: S4 has been implicated in NusA-dependent transcription antitermination PMID:28483689
Related studies in P. aeruginosa have characterized 30S assembly factors that work alongside uS4:
- RsgA (Small Ribosomal Subunit Biogenesis GTPase A) is involved in late stages of 30S maturation in P. aeruginosa [PMID:31199072, DOI:10.1111/febs.14959]
- RbfA (Ribosome-binding factor A) is a small ribosome assembly factor involved in 30S maturation [PMID:33157160, DOI:10.1016/j.bbagen.2020.129780]
Source: rpsD-deep-research-bioreason-sft.md
The BioReason SFT functional summary states:
A cytoplasmic small-subunit ribosomal protein that binds 16S rRNA to nucleate and stabilize early steps of 30S assembly on the platform, then remains as a structural organizer during translation. Its basic RNA-binding fold grips structured rRNA elements to shape the small-subunit architecture, recruit additional proteins, and maintain the geometry of the decoding environment, thereby supporting accurate and efficient protein synthesis.
This is largely accurate and well-articulated. The core claims -- 16S rRNA binding, nucleation of 30S assembly, structural role in the mature ribosome, and contribution to decoding accuracy -- are all supported by the literature and consistent with the curated review.
Minor errors and imprecisions:
"Platform" vs "body": The summary says uS4 nucleates assembly "on the platform." The UniProt/HAMAP annotation states it "nucleates assembly of the body of the 30S subunit." While uS4 is located near the platform region, the standard description refers to the "body" of the 30S. The BioReason thinking trace actually contains a similar inconsistency, mentioning both "the platform of the small subunit" and "body" in the same context.
Missing translational repressor role: uS4 has a well-characterized additional function as a translational autorepressor that regulates its own mRNA and the alpha operon mRNA in E. coli (PMID:28483689). While this has not been directly demonstrated in P. aeruginosa, it is a conserved feature of bacterial S4 proteins that the summary omits.
Missing transcription antitermination role: uS4 is also involved in transcription antitermination activities (PMID:28483689). This moonlighting function is not mentioned.
S4-S5 interface not explicitly named: The summary alludes to "the geometry of the decoding environment" but does not explicitly mention the S4-S5 interface, which is the mechanistic basis for uS4's role in translational fidelity (PMID:25548247). The literature shows that "the tRNA selection pathway involves a transition between the closed and open conformations of the 30S ribosomal subunit and requires disruption of the interface between the S4 and S5 proteins" (PMID:25548247).
What the summary gets right:
Comparison with interpro2go:
The ai-review.yaml contains GO_REF:0000002 (InterPro2GO) annotations for: RNA binding (GO:0003723, from IPR002942/IPR036986), structural constituent of ribosome (GO:0003735, from IPR005709), and small ribosomal subunit (GO:0015935, from IPR005709). BioReason's functional summary covers all of these interpro2go-level functions and goes substantially beyond them:
This demonstrates that BioReason is doing more than simply recapitulating interpro2go. The model synthesizes domain architecture knowledge with biological understanding of ribosome assembly and function. The functional summary reflects genuine biological insight about the role of S4-family proteins that goes beyond what automated domain-to-GO mappings provide.
The thinking trace is well-structured and demonstrates a coherent reasoning path from domain architecture to biological function. Notable aspects:
Overall, this is a well-reasoned trace that arrives at largely correct conclusions through sound structural-to-functional inference.
id: O52759
gene_symbol: rpsD
product_type: PROTEIN
status: DRAFT
taxon:
id: NCBITaxon:208964
label: Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 /
JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)
description: >-
Small ribosomal subunit protein uS4 (30S ribosomal protein S4) of Pseudomonas
aeruginosa PAO1. uS4 is a primary 16S rRNA-binding protein that nucleates
early assembly of the 30S ribosomal subunit body. It binds directly to 16S
rRNA, inducing conformational rearrangements required for recruitment of
secondary and tertiary binding proteins. In the mature 30S subunit, uS4
contributes to translational accuracy through its interface with uS5; disruption
of this interface during tRNA selection controls the transition between open
and closed conformations of the decoding center. The protein belongs to the
universal ribosomal protein uS4 family and contains an N-terminal domain and
a C-terminal S4 RNA-binding domain.
existing_annotations:
- term:
id: GO:0003735
label: structural constituent of ribosome
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: IBA annotation inferred from phylogenetic analysis (PANTHER). uS4
is a stable, stoichiometric component of the 30S ribosomal subunit whose
primary molecular function is to provide structural integrity to the
particle. It binds directly to 16S rRNA and is essential for 30S assembly
and stability. The BioReason SFT functional summary
(rpsD-deep-research-bioreason-sft.md) correctly identifies uS4 as a structural
organizer of the small subunit.
action: ACCEPT
reason: uS4 is unambiguously a structural constituent of the ribosome. It is
one of the primary binding proteins of the 30S subunit and remains stably
incorporated throughout the translation cycle. Multiple cryo-EM structures
confirm its integral position in the 30S subunit.
supported_by:
- reference_id: PMID:28483689
supporting_text: ribosomal protein uS4 helps initiate the assembly of the
small subunit by binding directly to 16S rRNA
- term:
id: GO:0015935
label: small ribosomal subunit
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: IBA annotation for cellular component localization to the small
ribosomal subunit. uS4 is a core component of the bacterial 30S subunit
confirmed by multiple cryo-EM structures of the P. aeruginosa 70S ribosome
(PDB 7UNR, 7UNV, 7UNW, 8RWG).
action: ACCEPT
reason: uS4 is resolved in multiple cryo-EM structures of the P. aeruginosa
70S ribosome at 2.5-2.9 A resolution, confirming its stable incorporation
into the 30S subunit.
supported_by:
- reference_id: PMID:28483689
supporting_text: ribosomal protein uS4 helps initiate the assembly of the
small subunit by binding directly to 16S rRNA
- term:
id: GO:0019843
label: rRNA binding
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: IBA annotation for rRNA binding. uS4 is one of the primary rRNA
binding proteins of the 30S subunit, binding directly to the 16S rRNA
where it nucleates assembly of the subunit body.
action: ACCEPT
reason: rRNA binding is the central molecular function of uS4. It binds 16S
rRNA directly and is one of the first proteins to associate with the rRNA
during in vitro 30S reconstitution. This has been extensively
characterized in E. coli and is conserved across bacteria.
supported_by:
- reference_id: PMID:17376481
supporting_text: Additionally, a temperature-dependent conformational
rearrangement was reported for a complex of primary r-protein S4 and 16
S rRNA
- reference_id: PMID:28483689
supporting_text: ribosomal protein uS4 helps initiate the assembly of the
small subunit by binding directly to 16S rRNA
- term:
id: GO:0042274
label: ribosomal small subunit biogenesis
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: IBA annotation for ribosomal small subunit biogenesis. uS4 is a
primary binding protein that initiates the 30S assembly pathway by binding
16S rRNA and inducing conformational changes that enable recruitment of
downstream assembly proteins.
action: ACCEPT
reason: uS4 is essential for 30S biogenesis as one of the primary binding
proteins that nucleates assembly. Temperature-dependent conformational
rearrangements of the S4-16S rRNA complex are required for downstream
assembly events. C-terminal truncations of uS4 cause assembly defects.
supported_by:
- reference_id: PMID:17376481
supporting_text: Some of the architectures achieved in these
rearrangements are consistent with subsequent downstream assembly events
such as assembly of the secondary and tertiary binding r-proteins
- reference_id: PMID:28483689
supporting_text: the C-terminal requirements for ribosome assembly are
less rigid than for mRNA decoding
- term:
id: GO:0003723
label: RNA binding
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: IEA annotation from InterPro2GO mapping (IPR002942 S4 RNA-binding
domain and IPR036986 S4 RNA-binding domain superfamily). RNA binding is
correct but less specific than rRNA binding (GO:0019843) which is already
annotated.
action: KEEP_AS_NON_CORE
reason: The S4 RNA-binding domain does indeed confer RNA binding activity.
However, the more specific rRNA binding (GO:0019843) is already annotated
via IBA and IEA evidence. This general RNA binding annotation is redundant
with the more specific term but not incorrect; uS4 also has mRNA binding
activity as a translational autorepressor in E. coli.
- term:
id: GO:0003735
label: structural constituent of ribosome
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: IEA annotation from InterPro2GO mapping (IPR005709 bacterial uS4
family). This duplicates the IBA annotation for the same term.
action: ACCEPT
reason: Correct InterPro2GO mapping. The bacterial uS4 family (IPR005709)
appropriately maps to structural constituent of ribosome. Consistent with
the IBA annotation above.
- term:
id: GO:0006412
label: translation
evidence_type: IEA
original_reference_id: GO_REF:0000120
review:
summary: IEA annotation from combined automated methods (UniRule/InterPro).
uS4 is an essential structural component of the 30S subunit required for
translation.
action: ACCEPT
reason: As a core 30S ribosomal protein, uS4 is directly involved in
translation. The mature 30S subunit containing uS4 participates in mRNA
decoding, and uS4 specifically contributes to translational accuracy via
its interaction with uS5 at the decoding center.
supported_by:
- reference_id: PMID:25548247
supporting_text: Ribosomal proteins S4 and S5 participate in the decoding
and assembly processes on the ribosome
- term:
id: GO:0015935
label: small ribosomal subunit
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: IEA annotation from InterPro2GO mapping (IPR005709). Duplicates the
IBA annotation for the same cellular component.
action: ACCEPT
reason: Correct InterPro2GO mapping consistent with all structural and
biochemical evidence for 30S subunit localization.
- term:
id: GO:0019843
label: rRNA binding
evidence_type: IEA
original_reference_id: GO_REF:0000120
review:
summary: IEA annotation from combined automated methods (UniRule mapping
from IPR001912, IPR018079, IPR022801). Duplicates the IBA annotation for
the same molecular function.
action: ACCEPT
reason: Correct automated annotation. Multiple InterPro signatures for uS4
domains all point to rRNA binding as the core molecular function.
- term:
id: GO:0022627
label: cytosolic small ribosomal subunit
evidence_type: NAS
original_reference_id: PMID:28483689
review:
summary: uS4 is a stable component of the bacterial cytosolic 30S ribosomal
subunit. This is more specific than GO:0015935 (small ribosomal subunit)
and accurately reflects that bacterial ribosomes are cytosolic. The
BioReason SFT trace (rpsD-deep-research-bioreason-sft.md) also correctly
infers cytosolic small ribosomal subunit localization.
action: NEW
reason: The existing annotations use GO:0015935 (small ribosomal subunit)
which is correct but does not specify the cytosolic compartment. Since P.
aeruginosa ribosomes are cytosolic, this more specific CC term is
warranted.
supported_by:
- reference_id: PMID:28483689
supporting_text: ribosomal protein uS4 helps initiate the assembly of the
small subunit by binding directly to 16S rRNA
- reference_id: file:PSEAE/rpsD/rpsD-deep-research-bioreason-sft.md
supporting_text: "[BioReason inferred] cytosolic small ribosomal subunit (GO:0022627)"
references:
- id: GO_REF:0000002
title: Gene Ontology annotation through association of InterPro records with
GO terms
findings: []
- id: GO_REF:0000033
title: Annotation inferences using phylogenetic trees
findings: []
- id: GO_REF:0000120
title: Combined Automated Annotation using Multiple IEA Methods
findings: []
- id: PMID:10984043
title: Complete genome sequence of Pseudomonas aeruginosa PAO1, an
opportunistic pathogen.
findings:
- statement: rpsD (PA4239) identified in the PAO1 genome, which encodes a
large complement of genes reflecting its environmental adaptability.
supporting_text: the sequence provides insights into the basis of the
versatility and intrinsic drug resistance of P. aeruginosa
- id: PMID:25548247
title: Modulation of decoding fidelity by ribosomal proteins S4 and S5.
findings:
- statement: S4 and S5 mutations alter translational accuracy; the S4-S5
interface controls decoding fidelity via open/closed 30S conformations.
supporting_text: Ribosomal proteins S4 and S5 participate in the decoding
and assembly processes on the ribosome and the interaction with specific
antibiotic inhibitors of translation
- statement: Mutations disrupting the S4-S5 interface cause ribosomal
ambiguity (ram) phenotypes with increased miscoding.
supporting_text: the tRNA selection pathway involves a transition between
the closed and open conformations of the 30S ribosomal subunit and
requires disruption of the interface between the S4 and S5 proteins
- id: PMID:28483689
title: The C-terminus of ribosomal protein uS4 contributes to small ribosomal
subunit biogenesis and the fidelity of translation.
findings:
- statement: uS4 C-terminal truncations cause both assembly defects and
increased miscoding, but assembly requirements are less stringent than
decoding requirements.
supporting_text: the C-terminal requirements for ribosome assembly are less
rigid than for mRNA decoding
- statement: uS4 has additional roles as a translational repressor and in
transcription antitermination.
supporting_text: uS4 is also a translational repressor ... and is involved
in transcription antitermination activities
- statement: uS4 is a primary binding protein that binds 16S rRNA directly to
initiate 30S assembly.
supporting_text: ribosomal protein uS4 helps initiate the assembly of the
small subunit by binding directly to 16S rRNA
- id: PMID:17376481
title: 'Temperature-dependent RNP conformational rearrangements: analysis of binary
complexes of primary binding proteins with 16 S rRNA.'
findings:
- statement: S4-16S rRNA complex undergoes temperature-dependent
conformational rearrangements that are prerequisite for downstream 30S
assembly.
supporting_text: Additionally, a temperature-dependent conformational
rearrangement was reported for a complex of primary r-protein S4 and 16 S
rRNA
- statement: Conformational changes in 16S rRNA induced by primary binding
proteins are consistent with sequential ribosome assembly.
supporting_text: Some of the architectures achieved in these rearrangements
are consistent with subsequent downstream assembly events such as assembly
of the secondary and tertiary binding r-proteins
- id: file:PSEAE/rpsD/rpsD-deep-research-bioreason-sft.md
title: BioReason-Pro SFT functional summary for rpsD
findings:
- statement: BioReason correctly identifies uS4 as a cytoplasmic small-subunit
ribosomal protein that binds 16S rRNA to nucleate 30S assembly and
maintain decoding geometry.
core_functions:
- description: >-
uS4 is a primary 16S rRNA-binding protein that provides structural integrity
to the 30S ribosomal subunit. It binds 16S rRNA directly during early
assembly, nucleating formation of the 30S body, and remains as a permanent
structural component. In the mature ribosome, uS4 contributes to
translational accuracy through its interface with uS5 at the decoding center.
molecular_function:
id: GO:0003735
label: structural constituent of ribosome
directly_involved_in:
- id: GO:0006412
label: translation
- id: GO:0042274
label: ribosomal small subunit biogenesis
in_complex:
id: GO:0022627
label: cytosolic small ribosomal subunit
supported_by:
- reference_id: PMID:28483689
supporting_text: ribosomal protein uS4 helps initiate the assembly of the
small subunit by binding directly to 16S rRNA
- reference_id: PMID:25548247
supporting_text: Ribosomal proteins S4 and S5 participate in the decoding
and assembly processes on the ribosome