Order of the two major head protein genes of bacteriophage phi 29 of Bacillus subtilis.

Bacteriophage phi 29 mutation sus8(22) has been mapped by two-factor crosses between markers sus8(769) and ts8(93). Whe sus8(22) infects Bacillus subtilis su- proteins, HP1 (major head protein) and HP3 (fiber protein) are not synthesized; instead, a fragment with a molecular weight of 25,000 is produced. The tryptic peptides of the fragments overlap with corresponding peptides in protein HP1, but not with the peptides of protein HP3, showing that cistron 8 codes for the major head protein HP1.