Analysis of a mutant amino acid-activating domain of surfactin synthetase bearing a serine-to-alanine substitution at the site of carboxylthioester formation.
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 activated 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.
Vollenbroich
D
D
Institut für Biochemie und Molekulare Biologie, Technische Universität Berlin, Germany.
Kluge
B
B
D'Souza
C
C
Zuber
P
P
Vater
J
J
D000409:Alanine / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis; D001483:Base Sequence; D004247:DNA; D055666:Lipopeptides; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D010453:Peptide Synthases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010456:Peptides, Cyclic; D015183:Restriction Mapping; D012694:Serine / Q000378:metabolism*
D001426:Bacterial Proteins; D055666:Lipopeptides; D009097:Multienzyme Complexes; D010456:Peptides, Cyclic; C009365:surfactin peptide; D012694:Serine; D004247:DNA; D010453:Peptide Synthases; C069542:surfactin synthetase; D000409:Alanine