title: Operon for biosynthesis of lipstatin, the Beta-lactone inhibitor of human pancreatic lipase.
abstract: Lipstatin, isolated from Streptomyces toxytricini as a potent and selective inhibitor of human pancreatic lipase, is a precursor for tetrahydrolipstatin (also known as orlistat, Xenical, and Alli), the only FDA-approved antiobesity medication for long-term use. Lipstatin features a 2-hexyl-3,5-dihydroxy-7,10-hexadecadienoic-β-lactone structure with an N-formyl-l-leucine group attached as an ester to the 5-hydroxy group. It has been suggested that the α-branched 3,5-dihydroxy fatty acid β-lactone moiety of lipstatin in S. toxytricini is derived from Claisen condensation between two fatty acid substrates, which are derived from incomplete oxidative degradation of linoleic acid based on feeding experiments. In this study, we identified a six-gene operon (lst) that was essential for the biosynthesis of lipstatin by large-deletion, complementation, and single-gene knockout experiments. lstA, lstB, and lstC, which encode two β-ketoacyl-acyl carrier protein synthase III homologues and an acyl coenzyme A (acyl-CoA) synthetase homologue, were indicated to be responsible for the generation of the α-branched 3,5-dihydroxy fatty acid backbone. Subsequently, the nonribosomal peptide synthetase (NRPS) gene lstE and the putative formyltransferase gene lstF were involved in decoration of the α-branched 3,5-dihydroxy fatty acid chain with an N-formylated leucine residue. Finally, the 3β-hydroxysteroid dehydrogenase-homologous gene lstD might be responsible for the reduction of the β-keto group of the biosynthetic intermediate, thereby facilitating the formation of the unique β-lactone ring.
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Tingli
authors.initials: T
authors.lastname: Bai
authors.affiliation: State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Daozhong
authors.initials: D
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Shuangjun
authors.initials: S
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Qingshan
authors.initials: Q
authors.lastname: Long
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Yemin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Ou
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Qianjin
authors.initials: Q
authors.lastname: Kang
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Zixin
authors.initials: Z
authors.lastname: Deng
authors.affiliation: State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China tao_meifeng@sjtu.edu.cn.
authors.forename: Meifeng
authors.initials: M
authors.lastname: Tao
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D053898:Biosynthetic Pathways; D004791:Enzyme Inhibitors / Q000378:metabolism*; D006801:Humans; D007783:Lactones / Q000378:metabolism*; D008049:Lipase / Q000037:antagonists & inhibitors*; D009876:Operon; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D007783:Lactones; C054164:lipstatin; D008049:Lipase; C518354:PNLIP protein, human