Peptidase S74 family, C-terminal intramolecular chaperone domain of Escherichia coli phage K1F endosialidase and related proteins
This peptidase S74 family includes C-terminal intramolecular chaperone domain (CIMCD) of Escherichia coli phage K1F endosialidase, Bacillus phage GA-1 neck appendage protein, and Bacteriophage T5 L-shaped tail fibre. This domain acts as a molecular chaperone; during virus particle assembly, the CIMCD of phage tailspike proteins induces the homo-trimerization of phage tailspike proteins by chaperoning the formation of a triple beta-helix. Homo-trimeric phage tailspike proteins are then auto-cleaved by the CIMCD domain. This family also includes the peptidase S74 Intramolecular Chaperone Auto-processing (ICA) domain of mammalian Myrf. The ICA domain drives the homo-oligomerization of Myrf in the endoplasmic reticulum (ER) membrane. The homo-oligomeric Myrf is proteolyzed by the ICA domain, releasing its N-terminal fragments from the ER membrane.
Jiyao W et al.(2023). "The conserved domain database in 2023.",