Synthesis of beauvericin by a multifunctional enzyme.
Beauvericin synthetase, a multifunctional enzyme catalyzing depsipeptide formation in Beauveria bassiana was purified to near homogeneity. The enzyme consists of a single polypeptide chain with a molecular mass of about 250 kdaltons. The mechanism of beauvericin formation is very similar to that of the cyclohexadepsipeptide enniatin. The constituents of the beauvericin molecule, L-phenylalanine and D-alpha-hydroxyisovaleric acid are activated as thioesters via the corresponding adenylates. N-Methylation takes place at the thioester bound stage of the phenylalanine residues. Omission of the methyl donor S-adenosyl-L-methionine results in the formation of demethylbeauvericin. Studies on substrate specificity revealed that phenylalanine could be replaced by a number of other aromatic or aliphatic amino acids like beta-phenylserine, ortho-, meta-, para-fluorophenylalanine, isoleucine, norleucine and leucine. Valine, the constituent amino acid of enniatin B was not accepted by the enzyme.
Peeters
H
H
Institut für Biochemie und Molekulare Biologie, Technische Universität Berlin, West Germany.
Zocher
R
R
Kleinkauf
H
H
D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D047630:Depsipeptides; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008745:Methylation; D003904:Mitosporic Fungi / Q000201:enzymology; D008970:Molecular Weight; D010453:Peptide Synthases / Q000032:analysis*; D010455:Peptides; D010456:Peptides, Cyclic / Q000096:biosynthesis; D013379:Substrate Specificity; D013696:Temperature
D000900:Anti-Bacterial Agents; D047630:Depsipeptides; D010455:Peptides; D010456:Peptides, Cyclic; C004456:beauvericin; D010453:Peptide Synthases; C055861:beauvericin synthetase