Structural Basis for the Reaction Mechanism of UDP-Glucose Pyrophosphorylase

• DOI: 10.1007/s10059-010-0047-6
• Publication Date: 2010-03-17T17:27:35Z
• Authors: Hun Kim; Jongkeun Choi; Truc Kim; Neratur K. Lokanath; Sung Chul Ha; Se Won Suh; Hye-Yeon Hwang; Kyeong Kyu Kim
• Keywords: Models, Molecular; Uridine Diphosphate Glucose; 0301 basic medicine; 570; Helicobacter pylori; Molecular Structure; UTP-Glucose-1-Phosphate Uridylyltransferase; Protein Conformation; Physics; Glucosephosphates; Quantitative Structure-Activity Relationship; Calorimetry; 540; Crystallography, X-Ray; Catalysis; Protein Structure, Tertiary; Substrate Specificity; Kinetics; 03 medical and health sciences; Bacterial Proteins; Models, Chemical; Catalytic Domain; Mutation; Magnesium

UDP-glucose pyrophosphorylases (UGPase; EC 2.7.7.9) catalyze the conversion of UTP and glucose-1-phosphate to pyrophosphate vice versa. Prokaryotic UGPases are distinct from their eukaryotic counterparts considered appropriate targets for development novel antibacterial agents since product, UDP-glucose, is indispensable biosynthesis virulence factors such as lipopolysaccharides capsular polysaccharides. In this study, crystal structures UGPase Helicobacter pylori (HpUGPase) were determined in apo- UDP-glucose/Mg2+-bound forms at 2.9 Å 2.3 resolutions, respectively. HpUGPase a homotetramer its active site located deep pocket each subunit. Magnesium ion coordinated by Asp130, two oxygen atoms phosphoryl groups, three water molecules with octahedral geometry. Isothermal titration calorimetry analyses demonstrated that Mg2+ plays key role enzymatic activity enhancing binding or suggesting reaction catalyzed an ordered sequential Bi mechanism. Furthermore, structure explains specificity uracil bases. The current structural study combined functional provides essential information understanding mechanism bacterial UGPases, well platform agents.