1.W.8. The (Enterobacterial phage T4) Portal Protein 8 (PPP8) Family
The phage T4 protein forms the portal vertex of the capsid (Michaud et al. 1989; Padilla-Sanchez et al. 2014). This portal plays critical roles in head assembly, genome packaging, neck/tail attachment, and genome ejection into the cytoplasm of the host cell. The portal protein multimerizes as a single ring-shaped homododecamer arranged around a central channel and binds to the terminase subunits to form the packaging machine. It attaches to the host inner membrane, most likely through interaction with the host YidC protein and forms together with chaperone gp40 an initiator complex to form the prohead Fokine et al. 2004; Quinten and Kuhn 2012).
This family belongs to the: Phage Portal Protein (PPP) Superfamily.
References associated with 1.W.8 family:
Fokine, A., P.R. Chipman, P.G. Leiman, V.V. Mesyanzhinov, V.B. Rao, and M.G. Rossmann. (2004). Molecular architecture of the prolate head of bacteriophage T4. Proc. Natl. Acad. Sci. USA 101: 6003-6008. 15071181
Michaud, G., A. Zachary, V.B. Rao, and L.W. Black. (1989). Membrane-associated assembly of a phage T4 DNA entrance vertex structure studied with expression vectors. J. Mol. Biol. 209: 667-681. 2685327
Padilla-Sanchez, V., S. Gao, H.R. Kim, D. Kihara, L. Sun, M.G. Rossmann, and V.B. Rao. (2014). Structure-function analysis of the DNA translocating portal of the bacteriophage T4 packaging machine. J. Mol. Biol. 426: 1019-1038. 24126213
Quinten, T.A. and A. Kuhn. (2012). Membrane interaction of the portal protein gp20 of bacteriophage T4. J. Virol. 86: 11107-11114. 22855489