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Title: Triosephosphate isomerase I170V alters catalytic site, enhances stability and induces pathology in a Drosophila model of TPI deficiency

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 TPII170V elicits behavioral abnormalities in Drosophila. An examination of hTPII170V enzyme kinetics revealed this substitution reduced catalytic turnover, while assessments of thermal stability demonstrated an increase in enzyme stability. Furthermore, the crystal structure of the homodimeric I170V mutant reveals changes in the geometry of critical residues within the catalytic pocket. In the end, collectively these data reveal new observations of the structural and kinetic determinants of TPI deficiency pathology, providing new insights into disease pathogenesis.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [3] ;  [2] ;  [4] ;  [3] ;  [5] ;  [1]
  1. Univ. of Pittsburgh School of Medicine, PA (United States). Dept. of Pharmacology & Chemical Biology; Univ. of Pittsburgh School of Medicine, PA (United States). Pittsburgh Inst. for Neurodegenerative Diseases (PIND)
  2. Univ. of Pittsburgh, PA (United States). Dept. of Biological Sciences
  3. Univ. of Pittsburgh School of Medicine, PA (United States). Pittsburgh Inst. for Neurodegenerative Diseases (PIND); Univ. of Pittsburgh School of Medicine, PA (United States). Dept. of Structural Biology
  4. Brookhaven National Lab. (BNL), Upton, NY (United States). Dept. of Biology
  5. Univ. of Pittsburgh, PA (United States). Dept. of Biological Sciences; Univ. of Pittsburgh School of Medicine, PA (United States). Dept. of Structural Biology
Publication Date:
OSTI Identifier:
1281085
Grant/Contract Number:
R01-GM103369 MJP; APV, R01-GM097204-APV; T32-GM8424-17 BPR
Type:
Accepted Manuscript
Journal Name:
Biochimica et Biophysica Acta. Molecular Basis of Disease
Additional Journal Information:
Journal Volume: 1852; Journal Issue: 1; Journal ID: ISSN 0925-4439
Publisher:
Elsevier
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE; National Inst. of Health (NIH)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES Triosephosphate isomerase; Drosophila; structure; Triosephosphate isomerase deficiency