The part of the srfA operon of Bacillus subtilis that contains the region required for competence development is composed of the first four amino acid- activating domains which are responsible for the incorporation of Glu, Leu, D-Leu, and Val into the peptide moiety of the lipopeptide surfactin. Ser-to- Ala substitutions were made in the amino-acylation site of each domain, and their effects on surfactin production and competence development were examined. All of the mutations conferred a surfactin-negative phenotype, supporting the finding that the conserved Ser in the amino-acylation site is required for peptide synthesis. However, none of the mutations affected significantly competence development or the expression of a lacZ fusion to the late competence operon comG. This, coupled with recent findings that only the fourth, Val-activating, domain is required for competence, suggests that some activity, other than amino-acylation and perhaps unrelated to peptide synthesis, possessed by the fourth domain is involved in the role of srfA in regulating competence development.
ASJC Scopus subject areas
- Molecular Biology