This family represents T4 phage gp25 protein and gp25-like proteins, found in several systems, including contractile tail bacteriophages, the type VI secretion system (T6SS) and R-type pyocins, which constitute a multiprotein tubular apparatus to att ...
This family represents T4 phage gp25 protein and gp25-like proteins, found in several systems, including contractile tail bacteriophages, the type VI secretion system (T6SS) and R-type pyocins, which constitute a multiprotein tubular apparatus to attach to and penetrate host cell membranes. Gp25 is a component of the conserved wedge in the inner part of the baseplate and serves as a nucleus for sheath polymerisation, playing a critical role in sheath assembly and contraction [1,2]. The EPR motif (Glu-Pro-Arg, residues 85-87 of gp25) is conserved across all members of the family including orthologues from the RpoS-mediated general stress response system (called IraD) [3,4]. This motif interacts with the 'core bundle' composed of orthologues of T4 gp6 and gp7 proteins in contractile injection systems.