title: A new salicylate synthase AmS is identified for siderophores biosynthesis in Amycolatopsis methanolica 239(T).
abstract: Siderophores are important for the growth of bacteria or the applications in treatment of iron overload-associated diseases due to the iron-chelating property. Salicylate synthase played a key role in the biosynthesis of some NRPS-derived siderophores by the providing of an iron coordination moiety as the initial building block. A new salicylate synthase, namely AmS, was identified in the biosynthesis pathway of siderophore amychelin in Amycolatopsis methanolica 239(T), since it shunt chorismate, an integrant precursor, from primary to secondary metabolite flow. The amino acid sequence alignment and phylogenetic analysis showed that AmS grouped into a new cluster. In vitro assays of AmS revealed its wide temperature tolerance ranged from 0 to 40 °C and narrow pH tolerant ranged from 7.0 to 9.0. AmS was resistant to organic solvents and non-ionic detergents. Moreover, AmS converted chorismate to salicylate with K m of 129.05 μM, k cat of 2.20 min(-1) at optimal conditions, indicating its low substrate specificity and comparable velocity to reported counterparts (Irp9 and MbtI). These properties of AmS may improve the iron-seizing ability of A. methanolica to compete with its neighbors growing in natural environments. Most importantly, serine and cysteine residues were found to be important for the catalytic activity of AmS. This study presented AmS as a new cluster of salicylate synthase and the reaction mechanism and potential applications of salicylate synthase were highlighted as well.
authors.affiliation: School of Life Sciences, University of Science and Technology of China, No. 443 HuangShan Road, Hefei, 230061, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Xie
authors.forename: Shengwang
authors.initials: S
authors.lastname: Dai
authors.forename: Jinzhao
authors.initials: J
authors.lastname: Shen
authors.forename: Biao
authors.initials: B
authors.lastname: Ren
authors.forename: Pei
authors.initials: P
authors.lastname: Huang
authors.forename: Qiushui
authors.initials: Q
authors.lastname: Wang
authors.forename: Xueting
authors.initials: X
authors.lastname: Liu
authors.forename: Buchang
authors.initials: B
authors.lastname: Zhang
authors.forename: Huanqin
authors.initials: H
authors.lastname: Dai
authors.forename: Lixin
authors.initials: L
authors.lastname: Zhang
mesh_terms: D039903:Actinobacteria / Q000201:enzymology* / Q000378:metabolism*; D001711:Biotransformation; D002827:Chorismic Acid / Q000378:metabolism; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008190:Lyases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012459:Salicylates / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D017262:Siderophores / Q000096:biosynthesis*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D012459:Salicylates; D017262:Siderophores; D008190:Lyases; C022620:salicylate synthetase; D002827:Chorismic Acid