SPP1 holin family

The SPP1 Holin (SPP1 Holin) Family (TC# 1.E.31) consists of proteins of between 90 and 160 amino acyl residues (aas) in length that exhibit two transmembrane segments (TMSs). SPP1 is a virulent double-stranded DNA (dsDNA) phage that infects the Gram-positive bacterium Bacillus subtilis strain 168, and likely others. SPP1 belongs to the Siphoviridae family. Although annotated as holins, members of the SPP1 family are not yet functionally characterized. A representative list of proteins belonging to the SPP1 Holin family can be found in Transporter Classification Database.