Biochemistry and general genetics of nonribosomal peptide synthetases in fungi.

Peptides like penicillin or cyclosporin are nonribosomally synthesised by large multifunctional enzymes. Peptide synthetase genes are coexpressed with other biosynthesis genes organised in clusters. Such clusters are common in fungal genomes, and the respective products are thought to be advantageous though not essential for survival. The biochemistry of the sequential polymerisation reactions is reviewed, including multienzyme organization, amino acid activation and modification reactions.