This family represents a conserved region located towards the N-terminal end of prophage tail length tape measure protein (TMP). TMP is important for assembly of phage tails and involved in tail length determination. Mutated forms TMP cause tail fibres to be shortened [1].

1: Mutational analysis of two structural genes of the temperate lactococcal bacteriophage TP901-1 involved in tail length determination and baseplate assembly. Pedersen M, Ostergaard S, Bresciani J, Vogensen FK; Virology 2000;276:315-328. PMID:11040123