In general, these proteins are thought to play a role in regulated cell death, although functionality varies between families and individual members.
The Holin superfamily II includes the TC families: All four of these families are derived from Pseudomonadota and are of relatively small sizes, the average size of the proteins within the entire superfamily is 78 ± 14 amino acyl residues (aas).
Some exceptions can be found (i.e., Lysis S family protein with 720 aas, TC# 1.E.1.1.7).
As in holin superfamily I, proteins in these families generally exhibit of 2 transmembrane spanners (TMSs).
Families 1 and 6 in Superfamily II are recognized domains in the Conserved Domains Database (CDD) as Lysis S and PHA00426 superfamilies, respectively, while families 7, and 25 lack recognized conserved domains.