title: Triosephosphate isomerase I170V alters catalytic site, enhances stability and induces pathology in a Drosophila model of TPI deficiency.
abstract: Triosephosphate isomerase (TPI) is a glycolytic enzyme which homodimerizes for full catalytic activity. Mutations of the TPI gene elicit a disease known as TPI Deficiency, a glycolytic enzymopathy noted for its unique severity of neurological symptoms. Evidence suggests that TPI Deficiency pathogenesis may be due to conformational changes of the protein, likely affecting dimerization and protein stability. In this report, we genetically and physically characterize a human disease-associated TPI mutation caused by an I170V substitution. Human TPI(I170V) elicits behavioral abnormalities in Drosophila. An examination of hTPI(I170V) enzyme kinetics revealed this substitution reduced catalytic turnover, while assessments of thermal stability demonstrated an increase in enzyme stability. The crystal structure of the homodimeric I170V mutant reveals changes in the geometry of critical residues within the catalytic pocket. Collectively these data reveal new observations of the structural and kinetic determinants of TPI Deficiency pathology, providing new insights into disease pathogenesis.
authors.affiliation: Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
authors.forename: Bartholomew P
authors.initials: BP
authors.lastname: Roland
authors.affiliation: Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Amrich
authors.affiliation: Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Kammerer
authors.affiliation: Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Stuchul
authors.affiliation: Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
authors.forename: Samantha B
authors.initials: SB
authors.lastname: Larsen
authors.affiliation: Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
authors.forename: Sascha
authors.initials: S
authors.lastname: Rode
authors.affiliation: Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
authors.forename: Anoshé A
authors.initials: AA
authors.lastname: Aslam
authors.affiliation: Department of Biology, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Annie
authors.initials: A
authors.lastname: Heroux
authors.affiliation: Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
authors.forename: Ronald
authors.initials: R
authors.lastname: Wetzel
authors.affiliation: Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA; Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: VanDemark
authors.affiliation: Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA. Electronic address: mjp44@pitt.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Palladino
mesh_terms: D000746:Anemia, Hemolytic, Congenital Nonspherocytic / Q000201:enzymology / Q000473:pathology*; D000818:Animals; D001522:Behavior, Animal; D002239:Carbohydrate Metabolism, Inborn Errors / Q000201:enzymology / Q000473:pathology*; D020134:Catalytic Domain; D004195:Disease Models, Animal; D004330:Drosophila; D004795:Enzyme Stability; D006801:Humans; D009154:Mutation; D014305:Triose-Phosphate Isomerase / Q000737:chemistry / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism*
chemical_list: D014305:Triose-Phosphate Isomerase
keywords: Drosophila; Structure; Triosephosphate isomerase; Triosephosphate isomerase deficiency