title: Construction of the octose 8-phosphate intermediate in lincomycin A biosynthesis: characterization of the reactions catalyzed by LmbR and LmbN.
abstract: Lincomycin A is a potent antimicrobial agent noted for its unusual C1 methylmercapto-substituted 8-carbon sugar. Despite its long clinical history for the treatment of Gram-positive infections, the biosynthesis of the C(8)-sugar, methylthiolincosamide (MTL), is poorly understood. Here, we report our studies of the two initial enzymatic steps in the MTL biosynthetic pathway leading to the identification of D-erythro-D-gluco-octose 8-phosphate as a key intermediate. Our experiments demonstrate that this intermediate is formed via a transaldol reaction catalyzed by LmbR using D-fructose 6-phosphate or D-sedoheptulose 7-phosphate as the C(3) donor and D-ribose 5-phosphate as the C(5) acceptor. Subsequent 1,2-isomerization catalyzed by LmbN converts the resulting 2-keto C(8)-sugar (octulose 8-phosphate) to octose 8-phosphate. These results provide, for the first time, in vitro evidence for the biosynthetic origin of the C(8) backbone of MTL.
authors.affiliation: Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Eita
authors.initials: E
authors.lastname: Sasaki
authors.forename: Chia-I
authors.initials: CI
authors.lastname: Lin
authors.forename: Ke-Yi
authors.initials: KY
authors.lastname: Lin
authors.forename: Hung-Wen
authors.initials: HW
authors.lastname: Liu
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000737:chemistry / Q000378:metabolism*; D055162:Biocatalysis; D019755:Carbon-Carbon Lyases / Q000737:chemistry / Q000378:metabolism*; D008034:Lincomycin / Q000096:biosynthesis* / Q000737:chemistry; D015394:Molecular Structure; D013403:Sugar Phosphates / Q000737:chemistry / Q000378:metabolism*
chemical_list: D013403:Sugar Phosphates; D008034:Lincomycin; D019755:Carbon-Carbon Lyases; D019747:Aldose-Ketose Isomerases