Genetic analysis of A domains. (A3 motif to the A6 motif) from nonribosomal peptide synthetases. The tree was constructed with TREECON  using the neighbor-joining method. All bootstrap values > 70% (1000 replicates) are shown next to the nodes. A domains from the cereulide synthetase (Ces) are printed in bold type. Abbreviations: Bac: bacitracin synthetase; Bar: barbamide synthetase; Css: cyclosporine synthetase; Esyn: Enniatin; Fen: fengycin synthetase; Grs: gramicidin S synthetase; Hts: HC-toxin; LicD: lichenysin synthetase; Myc: mycosubtilin synthetase; Nda: nodularin synthetase; Saf: Saframycin synthetase; Srf: surfactin synthetase; Tyc: tyrocidine A synthetase.