Structure and function of bacteriophage CBA120 ORF211 (TSP2), the determinant of phage specificity towards E. coli O157:H7.

摘要: The genome of Escherichia coli O157:H7 bacteriophage vB_EcoM_CBA120 encodes four distinct tailspike proteins (TSPs). TSPs, TSP1-4, attach to the phage baseplate forming a branched structure. We report 1.9 A resolution crystal structure TSP2 (ORF211), TSP that confers specificity towards E. O157:H7. shows N-terminal 168 residues involved in TSPs complex assembly are disordered absence partner proteins. ensuing head domain contains only first two fold modules seen other TSPs. catalytic site resides cleft at interface between adjacent trimer subunits, where Asp506, Glu568, and Asp571 located close proximity. Replacement Asp506 for alanine abolishes enzyme activity, thus identifying acid/base machinery. However, activity remains intact when mutated into asparagine residues. Analysis additional site-directed mutants background D506N:D571N mutant suggests engagement an alternative apparatus comprising Glu568 Tyr623. Finally, we demonstrate role interacting glutamate TSP1, Glu456 Glu483, underscoring diversity employed by