Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
Combined Automated Annotation using Multiple IEA Methods
The structure of gene product 6 of bacteriophage T4, the hinge-pin of the baseplate.
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Six gp6 dimers interdigitate via intra-wedge N-terminal dimers and inter-wedge C-terminal dimers to form a continuous ring that maintains baseplate integrity across the dome-to-star transition.
"Six gp6 dimers interdigitate, forming a ring that maintains the integrity of the baseplate in both conformations. One baseplate wedge contains an N-terminal dimer of gp6, whereas neighboring wedges are tied together through the C-terminal dimer of gp6."
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During baseplate rearrangement, the hinge angle between the N- and C-terminal parts of gp6 changes by ~15 degrees, expanding the gp6 ring diameter by 10 A.
"However, the hinge angle between the N- and C-terminal parts of gp6 changes by approximately 15 degrees , accounting for a 10 A radial increase in the diameter of the gp6 ring."
Structure of the bacteriophage T4 baseplate as determined by chemical cross-linking.
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Reversible chemical cross-linking of intact T4 baseplates identified direct contacts between wedge protein gp6 and central hub protein gp27.
"Most of the previous contacts were confirmed, and we report several new contacts, including those within the central hub (gp5-gptd2, gp26-gptd), between the hub and the outer wedges (gp6-gp27(2], between baseplate and sheath (gp54-gp18), and between sheath and core (gp19-gp18)."
Structure of the T4 baseplate and its function in triggering sheath contraction.
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Cryo-EM structures of the T4 baseplate in pre- and post-attachment states resolve the atomic architecture of the baseplate and its sheath contraction trigger mechanism.
"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."
UniProtKB record for P19060 (BP06_BPT4)
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gp6 is an inner baseplate protein involved in tail assembly and, as part of the gp25-(gp6)2-gp7 module, in triggering tail sheath contraction.
"Baseplate protein that is located next to the tail tube (inner baseplate) (PubMed:27193680). Involved in the tail assembly (PubMed:21129200). The gp25-(gp6)2-gp7 module is involved in sheath contraction (PubMed:27193680)."
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Twelve copies of gp6 form a continuous inner baseplate ring via N-terminal and C-terminal dimers and assemble with gp7 into a (gp6)2-gp7 heterotrimer.
"each gp6 molecule in the ring interacts with its two neighbors, forming an N-terminal dimer with one and a C-terminal dimer with the other (PubMed:27193680). Heterotrimer with gp7; gp6 is part of a (gp6)2-gp7 heterotrimeric molecule (PubMed:27193680)."
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Twelve copies of gp6 make up the continuous inner baseplate ring.
"Note=12 copies of gp6 form a continuous ring that makes up most of the inner baseplate."
Deep research report on bacteriophage T4 gene 6 (gp6; P19060)
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In the mature baseplate, 12 gp6 monomers form a ring of six dimers around the central hub.
"In the mature, dome-shaped T4 baseplate, gp6 is present as a **ring of six gp6 dimers** (i.e., 12 gp6 monomers) surrounding the central hub"
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During the dome-to-star transition, a ~15-degree hinge angle change between the N- and C-terminal domains of gp6 drives ring expansion and repositions the gp6 N-terminus to initiate tail sheath contraction.
"During dome→star rearrangement, gp6 preserves key dimer interfaces but the **hinge angle between N- and C-terminal parts changes (~15°)**, allowing **ring expansion**"
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Repositioning of the gp6 N-terminal region that contacts the first sheath ring (gp18) is proposed to initiate sheath contraction.
"This hinge motion repositions the gp6 N-terminal region that contacts the first sheath ring (gp18), and this repositioning is proposed to **initiate tail sheath contraction**"