title: Biochemical and structural characterization of Cryptosporidium parvum Lactate dehydrogenase.
abstract: The protozoan parasite Cryptosporidium parvum causes waterborne diseases worldwide. There is no effective therapy for C. parvum infection. The parasite depends mainly on glycolysis for energy production. Lactate dehydrogenase is a major regulator of glycolysis. This paper describes the biochemical characterization of C. parvum lactate dehydrogenase and high resolution crystal structures of the apo-enzyme and four ternary complexes. The ternary complexes capture the enzyme bound to NAD/NADH or its 3-acetylpyridine analog in the cofactor binding pocket, while the substrate binding site is occupied by one of the following ligands: lactate, pyruvate or oxamate. The results reveal distinctive features of the parasitic enzyme. For example, C. parvum lactate dehydrogenase prefers the acetylpyridine analog of NADH as a cofactor. Moreover, it is slightly less sensitive to gossypol inhibition compared with mammalian lactate dehydrogenases and not inhibited by excess pyruvate. The active site loop and the antigenic loop in C. parvum lactate dehydrogenase are considerably different from those in the human counterpart. Structural features and enzymatic properties of C. parvum lactate dehydrogenase are similar to enzymes from related parasites. Structural comparison with malate dehydrogenase supports a common ancestry for the two genes.
authors.affiliation: Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
authors.forename: William J
authors.initials: WJ
authors.lastname: Cook
authors.affiliation: Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
authors.forename: Olga
authors.initials: O
authors.lastname: Senkovich
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosintesis (CSIC/U. Sevilla), Avda. Americo Vespucio 49, Seville 41092, Spain.
authors.forename: Agustin
authors.initials: A
authors.lastname: Hernandez
authors.affiliation: Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
authors.forename: Haley
authors.initials: H
authors.lastname: Speed
authors.affiliation: Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States. Electronic address: debasish@uab.edu.
authors.forename: Debasish
authors.initials: D
authors.lastname: Chattopadhyay
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D016785:Cryptosporidium parvum / Q000201:enzymology*; D004789:Enzyme Activation; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009243:NAD / Q000737:chemistry / Q000378:metabolism; D009249:NADP / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D016415:Sequence Alignment; D013379:Substrate Specificity
chemical_list: D009243:NAD; D009249:NADP; D007770:L-Lactate Dehydrogenase
keywords: Cryptosporidium parvum; Crystal structure; Lactate dehydrogenase