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Acyl Transfer in Clorobiocin Biosynthesis: Involvement of Several Proteins in the Transfer of the Pyrrole‐2‐carboxyl Moiety to the Deoxysugar
Author(s) -
Freitag Anja,
Wemakor Emmanuel,
Li ShuMing,
Heide Lutz
Publication year - 2005
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200500252
Subject(s) - moiety , dna gyrase , streptomyces coelicolor , cosmid , pyrrole , stereochemistry , chemistry , gene cluster , streptomyces , polyketide , biosynthesis , streptomyces albus , biochemistry , combinatorial chemistry , biology , dna , gene , mutant , escherichia coli , bacteria , organic chemistry , genetics
Clorobiocin is an aminocoumarin antibiotic containing a pyrrole‐2‐carboxyl moiety, attached through an ester bond to a deoxysugar. The pyrrole moiety is important for the binding of the antibiotic to its biological target, gyrase. The complete biosynthetic gene cluster for clorobiocin has been cloned and sequenced from the natural producer, Streptomyces roseochromogenes DS 12.976. In this study, the genes cloN1 and cloN7 were deleted separately from a cosmid containing the complete clorobiocin cluster. The modified cosmids were introduced into the genome of the heterologous host Streptomyces coelicolor M512 by using the integration functions of the ΦC31 phage. While a heterologous producer strain harbouring the intact clorobiocin biosynthetic gene cluster accumulated clorobiocin, the cloN1 ‐ and cloN7 ‐defective integration mutants accumulated a clorobiocin derivative that lacked the pyrrole‐2‐carboxyl moiety, while also producing free pyrrole‐2‐carboxylic acid. The structures of these metabolites were confirmed by NMR and MS analysis. These results showed that CloN1 and CloN7, together with the previously investigated CloN2, are involved in the transfer of the pyrrole‐2‐carboxyl moiety to the deoxysugar of clorobiocin. A possible mechanism for the role of these three proteins in the acyl‐transfer process is suggested.