title: Deciphering the biosynthesis pathway of the antitumor thiocoraline from a marine actinomycete and its expression in two streptomyces species.
abstract: Thiocoraline is a thiodepsipeptide antitumor compound produced by two actinomycetes Micromonospora sp. ACM2-092 and Micromonospora sp. ML1, isolated from two marine invertebrates (a soft coral and a mollusc) found of the Indian Ocean coast of Mozambique. By using oligoprimers derived from nonribosomal peptide synthetase (NRPS) consensus sequences, six PCR fragments containing putative NRPS adenylation domains were amplified from the chromosome of Micromonospora sp. ML1. Insertional inactivation of each adenylation domain showed that two of them generated nonproducing mutants, thereby indicating that these domains were involved in thiocoraline biosynthesis. Sequencing of a 64.6 kbp DNA region revealed the presence of 36 complete open reading frames (ORFs) and two incomplete ones. Heterologous expression of a region of about 53 kbp, containing 26 of the ORFs, in Streptomyces albus and S. lividans led to the production of thiocoraline in these streptomycetes. Surprisingly, the identified gene cluster contains more NRPS modules than expected on the basis of the number of amino acids of thiocoraline. TioR and TioS would most probably constitute the NRPS involved in the biosynthesis of the thiocoraline backbone, according to the colinearity of the respective modules. It is proposed that two other NRPSs, TioY and TioZ, could be responsible for the biosynthesis of a small peptide molecule which could be involved in regulation of the biosynthesis of thicoraline in Micromonospora sp. ML1. In addition, a pathway is proposed for the biosynthesis of the unusual starter unit, 3-hydroxy-quinaldic acid.
authors.affiliation: Departamento de Biología Funcional e Instituto Universitario de Oncología del Principado de Asturias (I.U.O.P.A), Universidad de Oviedo, 33006 Oviedo, Spain.
authors.forename: Felipe
authors.initials: F
authors.lastname: Lombó
authors.forename: Ana
authors.initials: A
authors.lastname: Velasco
authors.forename: Angelina
authors.initials: A
authors.lastname: Castro
authors.forename: Fernando
authors.initials: F
authors.lastname: de la Calle
authors.forename: Alfredo F
authors.initials: AF
authors.lastname: Braña
authors.forename: José M
authors.initials: JM
authors.lastname: Sánchez-Puelles
authors.forename: Carmen
authors.initials: C
authors.lastname: Méndez
authors.forename: José A
authors.initials: JA
authors.lastname: Salas
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism*; D047630:Depsipeptides / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D019156:Indian Ocean; D008847:Micromonospora / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D015394:Molecular Structure; D005810:Multigene Family; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism; D011804:Quinolines / Q000737:chemistry / Q000378:metabolism; D013302:Streptomyces / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D047630:Depsipeptides; D011804:Quinolines; C109005:thiocoraline; D010453:Peptide Synthases; C104385:non-ribosomal peptide synthase; C008898:quinaldic acid