1993 Fiscal Year Final Research Report Summary
Analysis of Allosteric mechanism in bacterial L-lactate dehydrogenases
| Project/Area Number |
04454069
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
応用生物化学・栄養化学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
OHTA Takahisa The Univ.of Tokyo, Faculty of Agric., Professor, 農学部, 教授 (30011844)
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| Project Period (FY) |
1992 – 1993
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| Keywords | L-Lactate dehydrogenase / Allosteric / X-Ray crystallography / Protein engineering / Substrate inhibition |
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| Research Abstract |
1. X-ray crystal analysis of mutant enzyme : Mutant enzymes in which arginine-173 or histidine-188 in FBP-binding site were replaced to glutamine or tyrosine were obtained. Preliminary analysis of the enzymes showed that the histidine residue is necessary for the binding of FBP.
2. Analysis of substrate inhibition : Replace experiments showed that serine-193 and serine-318 play an important role for determining Michaelis and inhibition constants.
3. X-ray analysis of crystal which comprises both T and R forms of the LDH : Crystal analysis revealed that there are enzyme molecules in both T and R states in a single crystal. Both molecular structure were analyzed in 2.5 angstrom resolution.
4. Molecular mechanism of allosteric phenomena : Binding of FBP in T state overcomes electrostatic repulsion between subunits in P-axis. This induces rotation among four subunits and makes the active site active by interaction between subunit in Q-axis.
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