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Analysis of a mutant amino acid‐activating domain of surfactin synthetase bearing a serine‐to‐alanine substitution at the site of carboxylthioester formation
Author(s) -
Vollenbroich Dirk,
Kluge Britta,
D'Souza Cletus,
Zuber Peter,
Vater Joachim
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81077-d
Subject(s) - alanine , serine , chemistry , mutant , surfactin , amino acid substitution , amino acid , substitution (logic) , stereochemistry , biochemistry , biology , enzyme , genetics , gene , bacillus subtilis , bacteria , computer science , programming language
The reactive serine of the TGGHSL thioester binding motif of the first amino acid‐activating domain of surfactin synthetase was replaced by alanine using site‐directed mutagenesis. The multienzyme from cells of the resulting mutant lost its ability for thioester formation with l ‐Glu and was therefore inactive in surfactin production. The thiolation reactions catalyzed by the other amino acid‐activating domains of surfactin synthetase were not affected by the mutation. The results show that l ‐Glu is acativated at the first domain of surfactin synthetase, and give further evidence that a serine residue is essential for substrate amino acid activation at the reaction centers of peptide synthetases.