Naslov
Disruption of pre-polyketide and post-polyketide genes of the oxytetracycline gene cluster of Streptomyces rimosus

Autori
Petković, Hrvoje ; Perić, Nataša ; Zhou, Lihong ; Borovička, Branko ; Waterman, G. Peter ; Hranueli, Daslav ; Hunter, S. Iain

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
International Interdisciplinary Conference POLYKETIDES II: Chemistry, Biochemistry and Molecular Genedtics Book of Abstracts / Simpson, T.J. - London : Delhi : The Royal Society of Chemistry, 1998

Skup
International Interdisciplinary Conference POLYKETIDES II: Chemistry, Biochemistry and Molecular Genedtics

Mjesto i datum
Bristol, Ujedinjeno Kraljevstvo, 08.06.1998. - 10.06.1998

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Streptomyces rimosus; cyclase/aromatase; hydroxylase; disruption

Sažetak
The entire gene cluster for oxytetracycline (OTC) biosynthesis has been cloned from S. rimosus.1 A strategy to deduce the function of each gene is to identify the metabolite(s) made by a recombinant which has that gene disrupted.2 Gene disruptions of otcD1 and otcC were undertaken within the chromosome of S. rimosus. OtcD1 is thought to be involved in the folding, cyclization and aromatization of the hypothetical nonaketide intermediate in OTC biosynthesis (i.e. pre-polyketide), whereas OtcC hydroxylates the completed tetracyclic nucleus at C-61 (post-polyketide). Disruptions were achieved by inserting erythromycin (ermE), or gentamicin (gmr) resistance cassettes into plasmid-borne copies of the genes, (on an unstable bifunctional E. coli/Streptomyces vector or suicide vector, pIBI24) followed by double-crossover integration. The disrupted strains no longer produced OTC. OtcC::gmr produced two novel compounds, while otcD1::ermE produced a number of compounds, not detectable in the wild-type strain. These novel compounds contained 9, 15 and 17 C-atoms in their backbones instead of 19, as with OTC. Type II 'polyketide synthases' (PKS) (such as that for OTC) are thought to contain three to six separate mono- or bifunctional proteins, used iteratively for the assembly of the polyketide chain, in which the chain length determining gene (clf) specifes chain length.3 Neither otcD1 nor otcC is within the same cistron as clf. Our results support the conclusion4 that protein-protein interactions within a PKS complex may exert a profound influence on the nature of end products, and that post-polyketide enzymes may be associated with this complex. The absence of OtcD1 and OtcC, which are not part of the 'minimal PKS', leads to various polyketides with reduced numbers of carbon atoms. 1. Binnie, C., M. Warren & M. Butler. J. Bacteriol. 1989, 171, 887 2. Khosla, C., S. Ebert-Khosla and D.A. Hopwood. Mol. Microbiol. 1992, 21, 3237 3. Hopwood, D.A. Chem. Rev. 1997, 97, 2465 4. Leadlay, P.F. Curr. Op. Chem. Biol. 1997, 1, 162

Izvorni jezik
Engleski

Znanstvena područja
Prehrambena tehnologija

POVEZANOST RADA