Characterization of the Saframycin A Gene Cluster from Streptomyces lavendulae NRRL 11002 Revealing a Nonribosomal Peptide Synthetase System for Assembling the Unusual Tetrapeptidyl Skeleton in an Iterative Manner

Lei Li, Wei Deng, Jie Song, Wei Ding, Qun- Fei Zhao, Chao Peng, Wei- Wen Song, Gong -Li Tang and Wen Liu

Journal of Bacteriology 190 ( 1 ): 251 - 263 , 2008