title: The topological structure and function of Echinococcus granulosus lactate dehydrogenase, a tegumental transmembrane protein.
abstract: Lactate dehydrogenase (LDH), a terminal glycolytic enzyme, is generally considered as a cytosolic protein. We cloned lactate dehydrogenase from Echinococcus granulosus (EgLDH) and predicted it may be a membrane protein with two transmembrane regions through bioinformatics analysis. Intact worm immunofluorescence with antibodies prepared against linear B cell epitopes predicted in the region inside or outside of the membrane demonstrated that EgLDH spans the tegumental membrane twice, with the N terminal and C terminal all outside, just consistent with the putative topological structure. Then, the enzymatic characteristics and kinetic parameters of recombinant EgLDH were surveyed and the results suggested that EgLDH is responsible for catalyzing the reduction of pyruvic acid into lactic acid under physiological conditions. The enzymatic activity of the recombinant protein was inhibited by antibodies directed against the intact protein or against epitopes that contain key residues in the catalytic center or substrate binding sites. EgLDH is a potential target for drugs and vaccines against E. granulosus.
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Wenjia
authors.initials: W
authors.lastname: Gan
authors.forename: Zhaoping
authors.initials: Z
authors.lastname: Zhang
authors.forename: Gang
authors.initials: G
authors.lastname: Lv
authors.forename: Hongxu
authors.initials: H
authors.lastname: Xu
authors.forename: Suxiang
authors.initials: S
authors.lastname: Zeng
authors.forename: Yuzhe
authors.initials: Y
authors.lastname: Li
authors.forename: Weiping
authors.initials: W
authors.lastname: Wu
authors.forename: Xuchu
authors.initials: X
authors.lastname: Hu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D048209:Echinococcus granulosus / Q000201:enzymology*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D015801:Helminth Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera / Q000737:chemistry; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D017434:Protein Structure, Tertiary; D019289:Pyruvic Acid / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013696:Temperature
chemical_list: D015801:Helminth Proteins; D007106:Immune Sera; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D019289:Pyruvic Acid; D007770:L-Lactate Dehydrogenase