||The product, narbonolide, contains a 14-membered ring and is an intermediate in the biosynthesis of narbonomycin and pikromycin in the bacterium Streptomyces venezuelae. The enzyme also produces 10-deoxymethynolide (see EC 18.104.22.168, 10-deoxymethynolide synthase). The enzyme has 29 active sites arranged in four polypeptides (pikAI - pikAIV) with a loading domain, six extension modules and a terminal thioesterase domain. Each extension module contains a ketosynthase (KS), keto reductase (KR), an acyltransferase (AT) and an acyl-carrier protein (ACP). Not all active sites are used in the biosynthesis.
||Lu, H., Tsai, S.C., Khosla, C. and Cane, D.E. Expression, site-directed mutagenesis, and steady state kinetic analysis of the terminal thioesterase domain of the methymycin/picromycin polyketide synthase. Biochemistry 41 (2002) 12590–12597. [DOI] [PMID: 12379101]
||Kittendorf, J.D., Beck, B.J., Buchholz, T.J., Seufert, W. and Sherman, D.H. Interrogating the molecular basis for multiple macrolactone ring formation by the pikromycin polyketide synthase. Chem. Biol. 14 (2007) 944–954. [DOI] [PMID: 17719493]
||Yan, J., Gupta, S., Sherman, D.H. and Reynolds, K.A. Functional dissection of a multimodular polypeptide of the pikromycin polyketide synthase into monomodules by using a matched pair of heterologous docking domains. ChemBioChem 10 (2009) 1537–1543. [DOI] [PMID: 19437523]
||Whicher, J.R., Dutta, S., Hansen, D.A., Hale, W.A., Chemler, J.A., Dosey, A.M., Narayan, A.R., Hakansson, K., Sherman, D.H., Smith, J.L. and Skiniotis, G. Structural rearrangements of a polyketide synthase module during its catalytic cycle. Nature 510 (2014) 560–564. [DOI] [PMID: 24965656]