Comparative studies on the small Bacillus bacteriophages.

Abstract

As an aid to a more rational classification of small Bacillus phages that contain DNA with terminal protein, we have compared genome size, physical maps, and electrophoretic patterns of the structural proteins of five bacteriophages (.vphi.29, .vphi.15, Nf, M2Y and GA-1). In addition, we compared tryptic and chymotryptic peptides of the major structural protein of these phages. The results allow the following conclusions. Five small phages can be classified into three groups: group A (.vphi.29 and .vphi.15), group B (Nf and M2Y) and group C (GA-1). The peptide maps of the major head protein of M2Y and NF are very similar. On the other hand, the peptide maps of the GA-1 major head protein are not related to those of the other phages. Our present results suggest that although physical maps are quite different in group A and group B phages, the overall gene organization is similar in the two groups. On the other hand, group C phage, GA-1, is considerably different from the other two groups. These results argue that GA-1 phage have diverged very markedly from a common ancestor or were generated through a different evolutionary pathway.