Fig. 1.
Micrococcin structure and posttranslational processing. (A) Diagram depicting conversion of the TclE precursor peptide to mature MP1 when all eight biosynthetic proteins are expressed or to MP2 in the absence of TclS. (B) Engineered gene clusters for micrococcin production in B. subtilis. Left, the constitutive Pstrong promoter drives expression of GST–TclE from a cassette integrated into the thrC locus; Right, the xylose-inducible Pxyl promoter drives expression of tcl biosynthesis genes from a cassette integrated into the amyE locus. A TEV-protease cleavage site is incorporated between the GST-affinity tag and the TclE precursor peptide. (C) Summary of the seven chemical transformations required in micrococcin maturation and the enzymes predicted to carry them out.