FIG. 5.

Alignment of L. lactis and S. pyogenes phage RuvC homologs. Protein sequences from L. lactis phages bIL66 and bIL67 were chosen as representatives of the larger family of phage proteins. The bIL66 RuvC has percent identity values of 98, 96, and 93 to homologs from sk1, 712, and bIL170, respectively. bIL67 RuvC protein is 93% identical to those from c2 and vML3. Residues in boldtype in the E. coli RuvC sequence (Eco) represent those conserved among the eubacterial RuvC family (the structure of E. coli RuvC is represented under the sequence). Residues in boldtype in the bIL66, bIL67, and Spy (S. pyogenes) RuvC homologs represent matches with the E. coli RuvC sequence. Circles indicate the four acidic residues required for catalysis by E. coli RuvC; triangles mark residues thought to be involved in sequence specificity of Holliday junction resolution (3, 17). Residues considered similar are as follows: A and G; D and E; F, I, L, M, V, W, and Y; K and R; N and Q; and S and T.