GO_REF:0000002

Gene Ontology annotation through association of InterPro records with GO terms

GO_REF:0000043

Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping

PMID:27193680

Structure of the T4 baseplate and its function in triggering sheath contraction.

Atomic cryo-EM reconstruction of the T4 baseplate resolves the peripheral tail-fiber socket proteins and explains the conformational events leading to sheath contraction.

"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:BPT4/9/9-uniprot.txt

UniProtKB record for P10927 (BP09_BPT4)

gp9 is a peripheral baseplate protein that connects the long tail fibers to the baseplate, participates in tail assembly, and transmits the host-attachment signal for tail contraction.

"Peripheral baseplate protein that is part of the tail fiber network (PubMed:10545330, PubMed:27193680). Connects the long tail fibers to the baseplate and, after virus attachment to a host cell, probably changes its conformation to trigger the signal for tail contraction (PubMed:10545330). Involved in the tail assembly (PubMed:21129200)."
gp9 forms a homotrimer whose C-terminus binds the baseplate and whose N-terminal coiled-coil domain binds the proximal gp34 trimer of the long tail fiber.

"Homotrimer (PubMed:27193680). The gp9 trimer interacts with the long tail fiber (LTF) that comprises gp34 trimer, gp35, gp36 and a gp37 trimer."
The C-terminus of gp9 binds the baseplate while its N-terminal coiled-coil domain associates with the long tail fibers.

"The C-terminus is bound to the baseplate, and the N-terminus coiled-coil domain is associated with the long tail fibers."

file:BPT4/9/9-deep-research-falcon.md

Deep research report on bacteriophage T4 gene 9 (gp9; P10927)

gp9 forms the trimeric socket on the baseplate periphery that anchors the long tail fibers.

"gp9 forms the **attachment/socket point for the long tail fibers (LTFs)** on the baseplate"
Attachment of gp9 together with the gp11-gp12 complex after wedge assembly stabilizes the dome-shaped conformation of the baseplate.

"Pulse-chase analysis indicates **gp9 attaches after wedge assembly**, and this is followed by the simultaneous attachment of **gp11** and the **short tail fibers (gp12)**; together, gp9 and the gp11–gp12 complex stabilize the **dome-shaped baseplate** configuration"