Bacteriophage P21 holin S
Phage_holin_2_1 is a family of small hydrophobic holin proteins with one or more transmembrane domains. Members of this family fall into the holin superfamily II, and Phage 21 S holin is the prototype for this superfamily. It has two transmembrane segments with both the N- and C-termini on the cytoplasmic side of the inner membrane in E. coli. Holins are a diverse family of proteins that cause bacterial membrane lysis during late-protein synthesis. It is thought that the temporal precision of holin-mediated lysis may occur through the build up of a holin oligomer which causes the lysis.
Jiyao W et al.(2023). "The conserved domain database in 2023.",