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Characterisation of a Streptomyces antibioticus gene encoding a type I polyketide synthase which has an unusual coding sequence


A gene (ORFB) from Streptomyces antibioticus (an oleandomycin producer) encoding a large, multifunctional polyketide synthase (PKS) was cloned and sequenced. Its product shows an internal duplication and a close similarity to the third subunit of the PKS involved in erythromycin biosynthesis by Saccharopolyspora erythraea, showing the equivalent nine active site domains in the same order along the polypeptide. An unusual feature of this ORF is the GC content of most of the sequence, which is surprisingly low, for a Streptomyces gene; the large number of codons with T in the third position is particularly striking. The last 800 by of the gene stand out as being normal in their GC content, this region corresponding almost exactly to the thioesterase domain of the gene and suggesting that this domain was a late addition to the PKS. Based on the high degree of similarity between the ORFB product and the third subunit of the erythromycin PKS and the occurrence nearby of a gene conferring oleandomycin resistance, it is possible that this gene might be involved in the biosynthesis of the oleandomycin lactone ring.

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  1. Bevitt DJ, Cortés J, Haydock SF, Leadlay PF (1992) 6-Deoxyerythronolide-B synthase 2 from Saccharopolyspora erythraea. Cloning of the structural gene, sequence analysis and inferred domain structure of the multifunctional enzyme. Eur J Biochem 204:39–49

  2. Cortés J, Haydock SF, Roberts GA, Bevitt DJ, Leadlay PF (1990) An unusually large multifunctional polypeptide in the erythromycin-producing polyketide synthase of Saccharopolyspora erythraea. Nature 348:176–178

  3. Donadio S, Staver MJ, McAlpine JB, Swanson MJ, Katz L (1991) Modular organization of genes required for complex polyketide biosynthesis. Science 252:675–679

  4. Hopwood DA, Sherman DH (1990) Molecular genetics of polyketides and its comparison to fatty acid biosynthesis. Annu Rev Genet 24:37–66

  5. Lawlor EJ, Baylis HA, Chater KF (1987) Pleiotropical morphological and antibiotic deficiencies result from mutations in a gene encoding a tRNA-like product in Streptomyces coelicolor A3(2). Genes Dev 1:1305–1310

  6. Leskiw BK, Lawlor EJ, Fernández-Abalos JM, Chater KF (1991) TTA codons in some genes prevent their expression in a class of developmental, antibiotic-negative, Streptomyces mutants. Proc Natl Acad Sci USA 88:184–189

  7. Malpartida F, Hallam SE, Kieser HM, Motamedi H, Hutchinson CR, Butler MJ, Sugden DA, Warren M, McKillop C, Bailey CR, Humphreys GO, Hopwood DA (1987) Homology between Streptomyces genes coding for synthesis of different polyketides used to clone antibiotic biosynthetic genes. Nature 325:818–821

  8. Rodríguez AM, Olano C, Vilches C, Méndez C, Salas JA (1993) Streptomyces antibioticus contains at least three oleandomycin resistance determinants, one of which shows similarity with proteins of the ABC-transporter superfamily. Mol Microbiol 8:571–582

  9. Wright F, Bibb MJ (1992) Codon usage in the G+C-rich Streptomyces genome. Gene 113:55–65

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Correspondence to José A. Salas.

Additional information

Communicated by J. Lengeler

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Swan, D.G., Rodríguez, A.M., Vilches, C. et al. Characterisation of a Streptomyces antibioticus gene encoding a type I polyketide synthase which has an unusual coding sequence. Molec. Gen. Genet. 242, 358–362 (1994).

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Key words

  • Polyketides
  • Streptomyces
  • Oleandomycin
  • Gene fusion
  • Codon usage