title: Iterative Mechanism of Macrodiolide Formation in the Anticancer Compound Conglobatin.
abstract: Conglobatin is an unusual C2-symmetrical macrodiolide from the bacterium Streptomyces conglobatus with promising antitumor activity. Insights into the genes and enzymes that govern both the assembly-line production of the conglobatin polyketide and its dimerization are essential to allow rational alterations to be made to the conglobatin structure. We have used a rapid, direct in vitro cloning method to obtain the entire cluster on a 41-kbp fragment, encoding a modular polyketide synthase assembly line. The cloned cluster directs conglobatin biosynthesis in a heterologous host strain. Using a model substrate to mimic the conglobatin monomer, we also show that the conglobatin cyclase/thioesterase acts iteratively, ligating two monomers head-to-tail then re-binding the dimer product and cyclizing it. Incubation of two different monomers with the cyclase produces hybrid dimers and trimers, providing the first evidence that conglobatin analogs may in future become accessible through engineering of the polyketide synthase.
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK.
authors.forename: Annabel C
authors.initials: AC
authors.lastname: Murphy
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK.
authors.forename: Markiyan
authors.initials: M
authors.lastname: Samborskyy
authors.affiliation: Faculty of Technology, State University of Campinas UNICAMP, CEP 134840332 Limeira, São Paulo, Brazil.
authors.forename: Patricia
authors.initials: P
authors.lastname: Prediger
authors.affiliation: Institute of Chemistry, State University of Campinas, UNICAMP, C.P. 6154, CEP 13084-971 Campinas, São Paulo, Brazil.
authors.forename: Luiz Carlos
authors.initials: LC
authors.lastname: Dias
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK. Electronic address: pfl10@cam.ac.uk.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Leadlay
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000378:metabolism; D005798:Genes, Bacterial; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D005810:Multigene Family; D010080:Oxazoles / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D048630:Polyketide Synthases / Q000235:genetics / Q000378:metabolism; D013302:Streptomyces / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D010080:Oxazoles; C022800:conglobatin; D048630:Polyketide Synthases