title: Structural Basis for the Stereochemical Control of Amine Installation in Nucleotide Sugar Aminotransferases.
abstract: Sugar aminotransferases (SATs) are an important class of tailoring enzymes that catalyze the 5'-pyridoxal phosphate (PLP)-dependent stereo- and regiospecific installation of an amino group from an amino acid donor (typically L-Glu or L-Gln) to a corresponding ketosugar nucleotide acceptor. Herein we report the strategic structural study of two homologous C4 SATs (Micromonospora echinospora CalS13 and Escherichia coli WecE) that utilize identical substrates but differ in their stereochemistry of aminotransfer. This study reveals for the first time a new mode of SAT sugar nucleotide binding and, in conjunction with previously reported SAT structural studies, provides the basis from which to propose a universal model for SAT stereo- and regiochemical control of amine installation. Specifically, the universal model put forth highlights catalytic divergence to derive solely from distinctions within nucleotide sugar orientation upon binding within a relatively fixed SAT active site where the available ligand bound structures of the three out of four representative C3 and C4 SAT examples provide a basis for the overall model. Importantly, this study presents a new predictive model to support SAT functional annotation, biochemical study and rational engineering.
authors.forename: Fengbin
authors.initials: F
authors.lastname: Wang
authors.affiliation: Center for Pharmaceutical Research and Innovation, University of Kentucky College of Pharmacy , 789 South Limestone Street, Lexington, Kentucky 40536-0596, United States ;
authors.forename: Shanteri
authors.initials: S
authors.lastname: Singh
authors.forename: Weijun
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
authors.forename: Kate E
authors.initials: KE
authors.lastname: Helmich
authors.forename: Mitchell D
authors.initials: MD
authors.lastname: Miller
authors.forename: Hongnan
authors.initials: H
authors.lastname: Cao
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Bingman
authors.affiliation: Center for Pharmaceutical Research and Innovation, University of Kentucky College of Pharmacy , 789 South Limestone Street, Lexington, Kentucky 40536-0596, United States ;
authors.forename: Jon S
authors.initials: JS
authors.lastname: Thorson
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
authors.forename: George N
authors.initials: GN
authors.lastname: Phillips
mesh_terms: D000588:Amines / Q000737:chemistry / Q000378:metabolism*; D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D008847:Micromonospora / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D008958:Models, Molecular; D009711:Nucleotides / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D011732:Pyridoxal Phosphate / Q000378:metabolism; D013379:Substrate Specificity; D000637:Transaminases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000588:Amines; D000596:Amino Acids; D029968:Escherichia coli Proteins; D009711:Nucleotides; D011732:Pyridoxal Phosphate; D000637:Transaminases; C000608766:WecE protein, E coli