Accumulation of peptides by mycobacillin-negative mutants of Bacillus subtilis B3.
Thirteen mycobacillin-negative (My-) mutants of Bacillus subtilis B3 were isolated from an auxotrophically tagged mycobacillin producer organism. The wild-type producer, three feeble producers and three strictly My- mutants did not accumulate any ninhydrin-positive peptide in the culture medium while the remaining seven My- mutants did accumulate ten such peptides whose amino acid composition indicated that there might be only three different peptides. The N-terminal and C-terminal amino acid residues implicated one of these peptides as a pentapeptide intermediate in mycobacillin synthesis; this was further confirmed by its molecular weight and sequence. Studies on cell-free synthesis showed that only the enzyme system from the wild-type strain synthesized mycobacillin while the defective ones from all the My- mutants synthesized one and the same pentapeptide as found in the culture broth of some of the mutants. Further studies in which the enzymes responsible for mycobacillin synthesis by cell-free extracts were separated into three fractions, A, B and C, showed that seven of the mutants were defective in fraction B whereas the three other mutants had defects in both fractions B and C. Thus the pentapeptide Pro----Asp----Glu----Tyr----Asp appears to be implicated in mycobacillin biosynthesis.
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000935:Antifungal Agents; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism; D008970:Molecular Weight; D009154:Mutation; D009158:Mycobacillin / Q000096:biosynthesis / Q000235:genetics*; D010452:Peptide Biosynthesis
D000596:Amino Acids; D000935:Antifungal Agents; D009158:Mycobacillin