title: Identification of a type III polyketide synthase involved in the biosynthesis of spirolaxine.
abstract: Spirolaxine is a natural product isolated from Sporotrichum laxum ATCC 15155, which has shown a variety of biological activities including promising anti-Helicobacter pylori property. To understand how this compound is biosynthesized, the genome of S. laxum was sequenced. Analysis of the genome sequence revealed two putative type III polyketide synthase (PKS) genes in this strain, Sl-pks1 and Sl-pks2, which are located adjacent to each other (~2.0 kb apart) in a tail-to-tail arrangement. Disruption of these two genes revealed that Sl-PKS2 is the dedicated PKS involved in the biosynthesis of spirolaxine. The intron-free Sl-pks2 gene was amplified from the cDNA of S. laxum and ligated into the expression vector pET28a for expression in Escherichia coli BL21-CodonPlus (DE3)-RIL. The major products of Sl-PKS2 in E. coli were characterized as alkylresorcinols that contain a C13-C17 saturated or unsaturated hydrocarbon side chain based on the spectral data. This enzyme was purified and reacted with malonyl-CoA and a series of fatty acyl-SNACs (C6-C10). Corresponding alkylresorcinols were formed from the decarboxylation of the synthesized tetraketide resorcylic acids, together with fatty acyl-primed triketide and tetraketide pyrones as byproducts. This work provides important information about the PKS involved in the biosynthesis of spirolaxine, which will facilitate further understanding and engineering of the biosynthetic pathway of this medicinally important molecule.
authors.affiliation: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT, 84322-4105, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT, 84322-4105, USA.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT, 84322-4105, USA.
authors.forename: Shuwei
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT, 84322-4105, USA.|Department of Applied Chemistry and Biological Engineering, College of Chemical Engineering, Northeast Dianli University, Jilin, Jilin, 132012, China.
authors.forename: Dayu
authors.initials: D
authors.lastname: Yu
authors.affiliation: TCM and Ethnomedicine Innovation & Development Laboratory, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Qin
authors.affiliation: TCM and Ethnomedicine Innovation & Development Laboratory, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.
authors.forename: Huiyong
authors.initials: H
authors.lastname: Huang
authors.affiliation: TCM and Ethnomedicine Innovation & Development Laboratory, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China. wangwei402@hotmail.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT, 84322-4105, USA. jixun.zhan@usu.edu.|TCM and Ethnomedicine Innovation & Development Laboratory, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China. jixun.zhan@usu.edu.
authors.forename: Jixun
authors.initials: J
authors.lastname: Zhan
mesh_terms: D000217:Acyltransferases / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001572:Benzofurans / Q000378:metabolism* / Q000494:pharmacology; D053898:Biosynthetic Pathways / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D055785:Gene Knockdown Techniques; D016681:Genome, Fungal / Q000235:genetics*; D016480:Helicobacter pylori / Q000187:drug effects; D017422:Sequence Analysis, DNA; D013141:Spiro Compounds / Q000378:metabolism* / Q000494:pharmacology; D013175:Sporothrix / Q000235:genetics* / Q000378:metabolism*
chemical_list: C526075:5-hydroxy-7-methoxy-3-(5-(2-methyl-1,6-dioxaspiro(4,5)dec-7-yl)pentyl)-2-benzofuran-1(3H)-one; D001572:Benzofurans; D004271:DNA, Fungal; D013141:Spiro Compounds; D000217:Acyltransferases; C020141:flavanone synthetase
keywords: Anti-Helicobacter pylori; Biosynthesis; Gene disruption; Spirolaxine; Type III polyketide synthase