Characterization of Pseudomonas chlororaphis myovirus 201φ2-1 via genomic sequencing, mass spectrometry, and electron microscopy

Pseudomonas chlororaphis phage 201 phi 2-1 is a relative of Pseudomonas aeruginosa myovirus ( KZ. Phage 201 phi 2-1 was examined by complete genomic sequencing (316,674 bp), by a comprehensive mass spectrometry survey of its virion proteins and by electron microscopy. Seventy-six proteins, of which at least 69 have homologues in ( KZ, were identified by mass spectrometry. Eight proteins, in addition to the major head, tail sheath and tail tube proteins, are abundant in the virion. Electron microscopy of 201 phi 2-1 revealed a multitude of long, fine fibers apparently decorating the tail sheath protein. Among the less abundant virion proteins are three homologues to RNA polymerase beta or beta' subunits. Comparison between the genomes of 201 phi 2-1 and phi KZ revealed substantial conservation of the genome plan, and a large region with an especially high rate of gene replacement. The phi KZ-like phages exhibited a two-fold higher rate of divergence than for T4-like phages or host genomes. (C) 2008 Elsevier Inc. All rights reserved.