Alamethicin biosynthesis is hypothesized to be catalyzed by
alamethicin synthase, a
Nonribosomal peptide synthase (NRPS) first isolated in 1975. Although there are several sequences of the alamethicin peptide accepted, evidence suggests these all follow the general NRPS mechanism with small variations at select amino acids. Beginning with the
acylation of the N terminal of the first
aminoisobutiric acid on the ALM synthase enzyme by
Acetyl-CoA, this is followed by the sequential condensation of amino acids by each modular unit of the synthetase. Amino acids are initially adenylated by an “
adenylylation” (A) domain before being attached by a
thioester bond to an
Acyl Carrier Protein-like Peptidyl carrier protein. The growing chain is attached to the amino acid bearing PCP by the "condensation" (C) domain, followed by another round of the same reactions by the next module. Following addition of phenylalaninol the completed peptide chain is cleaved by the thioesterase domain, cleaving the thioester bond and leaving an alcohol. == References ==