Combined Automated Annotation using Multiple IEA Methods.

Cryo-EM structure of the bacteriophage T4 isometric head at 3.3-Å resolution and its relevance to the assembly of icosahedral viruses.

In the 3.3 A cryo-EM structure of the T4 isometric capsid, 660 copies of Soc form an external cage of 200 trimers clamping adjacent gp23* hexamers, with highest occupancy near the fivefold vertices where inter-capsomer angles and lattice strain are greatest.

"The capsid is further stabilized by Soc molecules, which form an external cage of 200 trimers, each clamping three adjacent capsomers."

file:BPT4/soc/soc-uniprot.txt

UniProtKB entry P03715 (SOC_BPT4)

Soc binds the outer surface of the expanded capsid after gp23 proteolytic cleavage and helps to stabilize the capsid against extremes of pH and temperature.

"Capsid decoration protein which helps to stabilize the capsid against extremes of pH and temperature."

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

Deep research literature synthesis for bacteriophage T4 gene soc

Soc is a nonessential capsid decoration clamp (~810-870 copies per wild-type prolate capsid) that bridges neighboring gp23* hexamers and stabilizes the head against alkaline pH (pH > 10.6) and thermal stress.

"**Soc (small outer capsid protein)** is a T4 head-shell accessory protein that **decorates the exterior surface** of the mature capsid and functions primarily as a **structural clamp (“glue”)** that reinforces the gp23* capsid lattice."