title: Characterization of the locus of genes encoding enzymes producing heptadepsipeptide micropeptin in the unicellular cyanobacterium Microcystis.
abstract: The gene cluster involved in producing the cyclic heptadepsipeptide micropeptin was cloned from the genome of the unicellular cyanobacterium Microcystis aeruginosa K-139. Sequencing revealed four genes encoding non-ribosomal peptide synthetases (NRPSs) that are highly similar to the gene cluster involved in cyanopeptolins biosynthesis. According to predictions based on the non-ribosomal consensus code, the order of the mcnABCE NPRS modules was well consistent with that of the biosynthetic assembly of cyclic peptides. The biochemical analysis of a McnB(K-139) adenylation domain and the knock-out of mcnC in a micropeptin-producing strain, M. viridis S-70, revealed that the mcn gene clusters were responsible for the production of heptadepsipeptide micropeptins. A detailed comparison of nucleotide sequences also showed that the regions between the mcnC and mcnE genes of M. aeruginosa K-139 retained short stretches of DNA homologous to halogenase genes involved in the synthesis of halogenated cyclic peptides of the cyanopeptolin class including anabaenopeptilides. This suggests that the mcn clusters of M. aeruginosa K-139 have lost the halogenase genes during evolution. Finally, a comparative bioinformatics analysis of the congenial gene cluster for depsipetide biosynthesis suggested the diversification and propagation of the NRPS genes in cyanobacteria.
authors.affiliation: Laboratory of Molecular Genetics, College of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan. anisitom@mail.ecc.u-tokyo.ac.jp
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Nishizawa
authors.forename: Akiko
authors.initials: A
authors.lastname: Ueda
authors.forename: Tomoyo
authors.initials: T
authors.lastname: Nakano
authors.forename: Akito
authors.initials: A
authors.lastname: Nishizawa
authors.forename: Takamasa
authors.initials: T
authors.lastname: Miura
authors.forename: Munehiko
authors.initials: M
authors.lastname: Asayama
authors.forename: Kiyonaga
authors.initials: K
authors.lastname: Fujii
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Harada
authors.forename: Makoto
authors.initials: M
authors.lastname: Shirai
mesh_terms: D047630:Depsipeptides / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D005798:Genes, Bacterial / Q000235:genetics*; D046931:Microcystis / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D015394:Molecular Structure; D005810:Multigene Family / Q000235:genetics*; D010453:Peptide Synthases / Q000235:genetics* / Q000378:metabolism*
chemical_list: D047630:Depsipeptides; D010453:Peptide Synthases; C104385:non-ribosomal peptide synthase