Fig. 7.

Organization of putative IVP genes in diverse podoviruses. Yellow—gene for tubular tail B, or tubular tail B homology in VpV262 gp52. As discussed in the text, this may reflect reuse of the end of the tubular tail B protein as an adhesin for the tail fiber, which may be composed of gp53 and gp54 in VpV262. SIO1 gp26.2 is an unannotated frame in the SIO1 GenBank entry. Brown—a gene belonging to an acetyltransferase family, including T7 IVP-A. Gray—a homolog of φRIO-1 gp39, which appears to be an alternative to IVP-A. Dark green—homolog of T7 IVP-B. Dark blue—homolog of φRIO-1 gp37. Cyan—homolog of T7 IVP-D. Black—a muralytic domain (murein D,D endopeptidase in the case of Pf-WMP3, and a murein β1,4 hydrolase or transglycosylase in the other cases). Light green—a homolog of epsilon15 gp16. Red—a homolog of φRIO-1 gp36. Rose-T7 IVP-C, and presumptive distant homolog of φRIO-1 gp36. m. (in H66)-a SAM-dependent methylase site. h. (in Pf-WMP3)-homing endonuclease. a.-displayed tubular tail A module in VpV262 consisting of a homolog of φRIO-1 gp45 and the gene for tubular tail A. b.-prospective tail fiber module in VpV262 consisting of a repeated C-terminal domain of the tubular tail B protein and an adjacent frame with similarity to polysaccharide lyase, f. – central fiber.