Approaches to stabilization of inter-domain recombination in polyketide synthase gene expression plasmids

• Published in: Journal of industrial microbiology & biotechnology 2003-03, Vol.30 (3), p.161-167
• Main Authors: HU, Z, DESAI, R. P, VOLCHEGURSKY, Y, LEAF, T, WOO, E, LICARI, P, SANTI, D. V, HUTCHINSON, C. R, MCDANIEL, R
• Format: Article
• Language: English
• Subjects: Amino acids; Base Sequence; Biological and medical sciences; Biosynthesis; Cloning; Codon - genetics; E coli; Enzymes; Fermentation; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation - genetics; Genetic Complementation Test; Genetic Engineering; Metabolites; Molecular Sequence Data; Multienzyme Complexes - chemistry; Multienzyme Complexes - genetics; Mutation; Plasmids; Plasmids - genetics; Recombination, Genetic - genetics; Streptomyces - enzymology; Streptomyces - genetics; Streptomyces coelicolor; Studies
• ISSN: 1367-5435; 1476-5535
• DOI: 10.1007/s10295-003-0029-1

Regions of extremely high sequence identity are recurrent in modular polyketide synthase (PKS) genes. Such sequences are potentially detrimental to the stability of PKS expression plasmids used in the combinatorial biosynthesis of polyketide metabolites. We present two different solutions for circumventing intra-plasmid recombination within the megalomicin PKS genes in Streptomyces coelicolor. In one example, a synthetic gene was used in which the codon usage was reengineered without affecting the primary amino acid sequence. The other approach utilized a heterologous subunit complementation strategy to replace one of the problematic regions. Both methods resulted in PKS complexes capable of 6-deoxyerythronolide B analogue biosynthesis in S. coelicolor CH999, permitting reproducible scale-up to at least 5-l stirred-tank fermentation and a comparison of diketide precursor incorporation efficiencies between the erythromycin and megalomicin PKSs.