Figure 2.

(A) Subunit and domain arrangement of the chloroeremomycin nonribosomal peptide synthetase. The following domains are indicated: adenylation (A), peptidyl carrier protein (PCP), condensation (C), epimerization (E), and thioesterase (TE). The expected amino acid precursors for each A domain are indicated. The identities of the amino acids activated by the first, second, and sixth A domains (A1, A2, and A6) were not clear at the outset: l-Leu may be methylated and/or epimerized before adenylation, and l-Tyr may be hydroxylated and/or chlorinated before adenylation. (B) Proteins cloned and expressed in E. coli in this study.