2dpg: Difference between revisions
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==Overview== | ==Overview== | ||
The catalytic mechanism of glucose 6-phosphate dehydrogenase from | The catalytic mechanism of glucose 6-phosphate dehydrogenase from Leuconostoc mesenteroides was investigated by replacing three amino acids, His-240, Asp-177, and His 178, with asparagine, using site-directed mutagenesis. Each of the mutant enzymes was purified to homogeneity and characterized by substrate binding studies and steady-state kinetic analyses. The three-dimensional structure of the H240N glucose 6-phosphate dehydrogenase was determined at 2.5 A resolution. The results support a mechanism in which His-240 acts as the general base that abstracts the proton from the C1-hydroxyl group of glucose 6-phosphate, and the carboxylate group of Asp-177 stabilizes the positive charge that forms on His-240 in the transition state. The results also confirm the postulated role of His-178 in binding the phosphate moiety of glucose 6-phosphate. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Leuconostoc mesenteroides]] | [[Category: Leuconostoc mesenteroides]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Adams, M | [[Category: Adams, M J.]] | ||
[[Category: Gover, S.]] | [[Category: Gover, S.]] | ||
[[Category: Naylor, C | [[Category: Naylor, C E.]] | ||
[[Category: Paludin, S.]] | [[Category: Paludin, S.]] | ||
[[Category: NAP]] | [[Category: NAP]] | ||
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[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:01:11 2008'' | ||