Baseplate wedge protein gp10 is a 602-residue homotrimeric structural protein (18 copies per virion) that forms the six peripheral pins of the bacteriophage T4 baseplate and initiates the sequential assembly of the outer baseplate wedge. Organized into four domains with non-collinear threefold axes and stabilized by disulfide bonds both within the gp10 trimer and to the backbone protein gp7, gp10 anchors the gp11 adaptor trimer and the N-terminus of the gp12 short tail fiber. During infection, gp10 rotates by approximately 100 degrees as the baseplate transitions from its dome-shaped to star-shaped conformation, acting as a mechanical lever that deploys the short tail fibers toward the Escherichia coli surface to establish irreversible attachment.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0019076 viral release from host cell | IEA GO_REF:0000002 | REMOVE | Summary: gp10 is a virion baseplate wedge pin and mechanical lever that functions in tail assembly and deployment of short tail fibers during viral attachment and entry, not in viral release from the host cell. Reason: This electronic annotation derives from an InterPro2GO mapping on domain family IPR008987 (Baseplate structural protein Gp9/Gp10, N-terminal domain), which is mis-mapped to viral release from host cell. Experimental structural and biochemical studies establish that gp10 is an extracellularly acting structural component of the virion baseplate that initiates outer wedge assembly and rotates during the dome-to-star transition to deploy the gp12 short tail fibers for host attachment, having no role in host cell lysis or viral egress. Supporting Evidence: file:BPT4/10/10-uniprot.txt Peripheral baseplate protein that is part of the tail fiber network. Connects the short tail fibers to the baseplate (PubMed:16554069). During infection, the baseplate undergoes a conformational change from a dome-shaped to a star-shaped structure. At this point, gp10 rotates and acts as a lever that unfolds the short tail fibers, which then interact with host cell surface receptors. Involved in the tail assembly. file:BPT4/10/10-deep-research-falcon.md High-resolution structural work describes gp10 as a **602-residue trimeric protein** organized into **four domains**, each forming a homotrimer, with **non-collinear trimer axes** that allow substantial reorientation during baseplate conformational switching. |
| GO:0098003 viral tail assembly | IEA GO_REF:0000043 | ACCEPT | Summary: gp10 initiates the sequential assembly of the six outer baseplate wedges by binding gp7 and recruiting the peripheral gp11 and gp12 tail fiber components. Reason: Classical in vitro reconstitution and atomic-resolution cryo-EM structures demonstrate that the gp10 homotrimer is the initial building block of the baseplate wedge assembly pathway, forming a disulfide-linked subcomplex with gp7 and providing the docking sites for gp11 and gp12 during tail morphogenesis. Supporting Evidence: file:BPT4/10/10-uniprot.txt Peripheral baseplate protein that is part of the tail fiber network. Connects the short tail fibers to the baseplate (PubMed:16554069). During infection, the baseplate undergoes a conformational change from a dome-shaped to a star-shaped structure. At this point, gp10 rotates and acts as a lever that unfolds the short tail fibers, which then interact with host cell surface receptors. Involved in the tail assembly. file:BPT4/10/10-deep-research-falcon.md High-resolution structural work describes gp10 as a **602-residue trimeric protein** organized into **four domains**, each forming a homotrimer, with **non-collinear trimer axes** that allow substantial reorientation during baseplate conformational switching. |
| GO:0098015 virus tail | IEA GO_REF:0000043 | MODIFY | Summary: gp10 is a component of the bacteriophage T4 tail, but this annotation is overly general compared to its specific localization in the tail baseplate. Reason: While gp10 is part of the viral tail, atomic structures of the T4 baseplate resolve six gp10 homotrimers specifically at the peripheral vertices of the tail baseplate. Modifying this broad term to GO:0098025 (virus tail, baseplate), which is already asserted on this gene, provides the precise localization. Proposed replacements: virus tail, baseplate Supporting Evidence: file:BPT4/10/10-uniprot.txt Homotrimer; disulfide-linked (PubMed:19896486, PubMed:27193680). Heteromultimer with gp7 (PubMed:19896486, PubMed:27193680); a gp10 molecule is disulfide-linked to gp7 and the other two remaining gp10 molecules form a disulfide bond (PubMed:27193680). The gp10 trimer interacts with gp11 trimer and with the short tail fiber (STF) composed of the gp12 trimer (PubMed:27193680). file:BPT4/10/10-deep-research-falcon.md In a crystallography + cryo-EM fitting study, the **whole gp10 rotates ~100° about its long axis**, and **domain IV rotates ~60°** during the hexagon→star transition. |
| GO:0098025 virus tail, baseplate | IEA GO_REF:0000120 | ACCEPT | Summary: Automated rule-based annotation accurately localizes gp10 to the viral tail baseplate. Reason: Consistent with atomic-resolution structural determination (PMID:27193680), six gp10 homotrimers form the peripheral pins of the bacteriophage T4 baseplate wedge. Supporting Evidence: PMID:27193680 Here we present the atomic structure of the approximately 6-megadalton bacteriophage T4 baseplate in its pre- and post-host attachment states and explain the events that lead to sheath contraction in atomic detail. file:BPT4/10/10-deep-research-falcon.md High-resolution structural work describes gp10 as a **602-residue trimeric protein** organized into **four domains**, each forming a homotrimer, with **non-collinear trimer axes** that allow substantial reorientation during baseplate conformational switching. |
| GO:0098025 virus tail, baseplate | IDA PMID:27193680 Structure of the T4 baseplate and its function in triggering... | ACCEPT | Summary: Atomic structures of the T4 baseplate directly resolve six gp10 homotrimers at the peripheral vertices of the baseplate wedge, disulfide-linked to gp7 and bound to gp11 and gp12. Reason: Direct structural evidence from X-ray crystallography and cryo-EM reconstruction of the T4 baseplate in pre- and post-attachment conformations confirms that gp10 is an integral structural component of the viral tail baseplate. Supporting Evidence: PMID:27193680 Here we present the atomic structure of the approximately 6-megadalton bacteriophage T4 baseplate in its pre- and post-host attachment states and explain the events that lead to sheath contraction in atomic detail. file:BPT4/10/10-uniprot.txt Homotrimer; disulfide-linked (PubMed:19896486, PubMed:27193680). Heteromultimer with gp7 (PubMed:19896486, PubMed:27193680); a gp10 molecule is disulfide-linked to gp7 and the other two remaining gp10 molecules form a disulfide bond (PubMed:27193680). The gp10 trimer interacts with gp11 trimer and with the short tail fiber (STF) composed of the gp12 trimer (PubMed:27193680). file:BPT4/10/10-deep-research-falcon.md In a crystallography + cryo-EM fitting study, the **whole gp10 rotates ~100° about its long axis**, and **domain IV rotates ~60°** during the hexagon→star transition. |
| GO:0039660 structural constituent of virion | IDA PMID:27193680 Structure of the T4 baseplate and its function in triggering... | NEW | Summary: Six disulfide-linked gp10 homotrimers (18 subunits) form the structural peripheral pins of the six baseplate wedges in the bacteriophage T4 virion. Reason: Atomic structures of the T4 baseplate (PMID:27193680) establish that gp10 is a core structural component of the virion baseplate periphery that scaffolds gp7, gp11, and the gp12 short tail fibers. Supporting Evidence: PMID:27193680 Here we present the atomic structure of the approximately 6-megadalton bacteriophage T4 baseplate in its pre- and post-host attachment states and explain the events that lead to sheath contraction in atomic detail. file:BPT4/10/10-uniprot.txt Peripheral baseplate protein that is part of the tail fiber network. Connects the short tail fibers to the baseplate (PubMed:16554069). During infection, the baseplate undergoes a conformational change from a dome-shaped to a star-shaped structure. At this point, gp10 rotates and acts as a lever that unfolds the short tail fibers, which then interact with host cell surface receptors. Involved in the tail assembly. |
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Download this section (compressed HTML)Q: How are the inter-chain disulfide bonds between gp10(Cys444) and gp7(Cys479) and between the remaining two gp10(Cys444) protomers formed inside the reducing Escherichia coli cytoplasm during baseplate wedge assembly?
Q: What is the exact sequence of inter-domain hinge motions among domains I–IV of gp10 that transduces long tail fiber binding signals via gp9 and gp11 into release of the gp12 short tail fibers?
Experiment: Perform site-directed mutagenesis of Cys444 in gp10 (C444S/C444A) and quantify wedge assembly yield, virion thermostability, and plating efficiency to determine whether the gp10-gp7 and gp10-gp10 disulfide bonds are essential for assembly or mechanical force transmission.
Hypothesis: Loss of Cys444 disulfide cross-links will destabilize the gp10-gp7 wedge pin interface and reduce the efficiency of dome-to-star conformational switching under mechanical load.
Experiment: Introduce engineered inter-domain disulfide staples across the flexible linkers connecting domains II, III, and IV of gp10 and assay short tail fiber deployment by cryo-EM and LPS-binding assays.
Hypothesis: Restricting inter-domain rotation of domain IV relative to domains I–III will lock gp12 in its stowed sub-baseplate conformation and prevent irreversible host adsorption.
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