Baseplate wedge protein gp11 is a 219-residue homotrimeric adaptor protein (18 copies per virion) situated at the six peripheral vertices of the bacteriophage T4 baseplate. Composed of an N-terminal three-stranded coiled-coil domain, a middle beta-roll finger domain, and a C-terminal beta-annulus domain, each gp11 trimer docks onto domain III of the gp10 wedge pin and clamps around the central hinge of the gp12 short tail fiber trimer. By stabilizing the stowed garland of short tail fibers in the dome-shaped baseplate and rotating alongside gp10 during the dome-to-star transition, gp11 couples host recognition by the long tail fibers to the deployment of gp12 for irreversible host adsorption.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0098003 viral tail assembly | IEA GO_REF:0000043 | ACCEPT | Summary: gp11 assembles onto the gp10 peripheral baseplate pin and is required for stable incorporation and organization of the gp12 short tail fibers into the mature phage tail baseplate. Reason: Biochemical reconstitution and cryo-EM/crystallographic studies show that gp11 trimers bind directly to gp10 during baseplate wedge maturation (or onto pre-assembled gp11-deficient baseplates) to anchor and stabilize the gp12 short tail fibers into a functional tail apparatus. Supporting Evidence: file:BPT4/11/11-uniprot.txt Baseplate protein that is part of the baseplate wedge and that connects the short tail fibers to the baseplate (PubMed:15315755). Involved in the tail assembly. file:BPT4/11/11-deep-research-falcon.md gp11 interacts with **gp10** during wedge initiation/assembly and associates functionally with **gp12 STFs**; gp11–gp12 association is part of stabilizing the dome-shaped baseplate. |
| GO:0098015 virus tail | IEA GO_REF:0000043 | MODIFY | Summary: gp11 is a structural component of the bacteriophage T4 tail, but this annotation is overly general given its well-defined localization within the tail baseplate. Reason: Atomic structures of the bacteriophage T4 tail resolve six gp11 homotrimers specifically at the peripheral vertices of the tail baseplate. Modifying GO:0098015 (virus tail) to its more specific child term GO:0098025 (virus tail, baseplate), which is already asserted on this gene, accurately reflects its localization. Proposed replacements: virus tail, baseplate Supporting Evidence: file:BPT4/11/11-uniprot.txt Homotrimer (PubMed:19896486, PubMed:27193680). The gp11 trimer interacts with gp10 trimer and with the short tail fiber (STF) composed of the gp12 trimer (PubMed:27193680). file:BPT4/11/11-deep-research-falcon.md Enterobacteria phage T4 gene product 11 (gp11; UniProt P10929) is a **structural baseplate wedge/pin protein** that forms a **trimeric adaptor** at the baseplate periphery and serves as a key **mechanical and signaling interface** between the **baseplate (via gp10)** and the **short tail fibers (gp12)** required for irreversible adsorption and triggering of contractile tail function. |
| GO:0098025 virus tail, baseplate | IEA GO_REF:0000043 | ACCEPT | Summary: Keyword-based annotation accurately assigns gp11 to the viral tail baseplate. Reason: Supported by X-ray crystallography and cryo-EM reconstructions (PMID:27193680) showing 18 copies (six homotrimers) of gp11 at the peripheral pins of the T4 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:BPT4/11/11-uniprot.txt Note=Present in 18 copies in the baseplate. file:BPT4/11/11-deep-research-falcon.md Enterobacteria phage T4 gene product 11 (gp11; UniProt P10929) is a **structural baseplate wedge/pin protein** that forms a **trimeric adaptor** at the baseplate periphery and serves as a key **mechanical and signaling interface** between the **baseplate (via gp10)** and the **short tail fibers (gp12)** required for irreversible adsorption and triggering of contractile tail function. |
| GO:0098025 virus tail, baseplate | IDA PMID:27193680 Structure of the T4 baseplate and its function in triggering... | ACCEPT | Summary: Atomic-resolution cryo-EM and crystallographic structures of the T4 baseplate resolve six gp11 homotrimers bound to gp10 and gp12 at the periphery of the baseplate wedge. Reason: Direct structural determination of the pre- and post-attachment T4 baseplate establishes gp11 as an integral component of the peripheral 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:BPT4/11/11-uniprot.txt Homotrimer (PubMed:19896486, PubMed:27193680). The gp11 trimer interacts with gp10 trimer and with the short tail fiber (STF) composed of the gp12 trimer (PubMed:27193680). file:BPT4/11/11-deep-research-falcon.md Enterobacteria phage T4 gene product 11 (gp11; UniProt P10929) is a **structural baseplate wedge/pin protein** that forms a **trimeric adaptor** at the baseplate periphery and serves as a key **mechanical and signaling interface** between the **baseplate (via gp10)** and the **short tail fibers (gp12)** required for irreversible adsorption and triggering of contractile tail function. |
| GO:0039660 structural constituent of virion | IDA PMID:27193680 Structure of the T4 baseplate and its function in triggering... | NEW | Summary: Six gp11 homotrimers (18 subunits) serve as structural adaptors at the peripheral vertices of the bacteriophage T4 baseplate, coupling gp10 to the gp12 short tail fibers. Reason: Atomic-resolution cryo-EM and crystallographic structures of the T4 baseplate (PMID:27193680) demonstrate that gp11 is an essential structural constituent of the virion baseplate periphery. 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:BPT4/11/11-uniprot.txt Baseplate protein that is part of the baseplate wedge and that connects the short tail fibers to the baseplate (PubMed:15315755). Involved in the tail assembly. |
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Download this section (compressed HTML)Q: How does transient binding of the P22 (gp37) distal tip of the long tail fiber to the gp11 finger domain in the dome-shaped baseplate modulate the threshold for triggering the dome-to-star transition?
Q: What is the molecular mechanism by which the gp11 finger domain releases the C-terminal receptor-binding head of the neighboring gp12 short tail fiber trimer while remaining clamped to the central shaft of its partner gp12 trimer?
Experiment: Mutate surface-exposed residues in the gp11 finger domain that contact the C-terminal head of the adjacent gp12 trimer in the dome-shaped state and measure the thermal activation barrier for spontaneous baseplate transition by cryo-EM and urea-triggering assays.
Hypothesis: Disrupting the gp11 clamp on the neighboring gp12 receptor-binding head will destabilize the stowed short tail fiber garland and lower the activation barrier for premature dome-to-star conversion.
Experiment: Perform surface plasmon resonance and cross-linking mass spectrometry between purified gp11 trimers and recombinant gp37 C-terminal fragments to map the putative long tail fiber docking interface on gp11.
Hypothesis: gp11 provides a low-affinity docking site that holds the long tail fibers in a retracted conformation prior to host receptor engagement.
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