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Title
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On the three-dimensional structure and catalytic mechanism of triose phosphate isomerase.
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Authors
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T.Alber,
D.W.Banner,
A.C.Bloomer,
G.A.Petsko,
D.Phillips,
P.S.Rivers,
I.A.Wilson.
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Ref.
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Philos Trans R Soc Lond B Biol Sci, 1981,
293,
159-171.
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PubMed id
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Abstract
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Triose phosphate isomerase is a dimeric enzyme of molecular mass 56 000 which
catalyses the interconversion of dihydroxyacetone phosphate (DHAP) and
D-glyceraldehyde-3-phosphate. The crystal structure of the enzyme from chicken
muscle has been determined at a resolution of 2.5 A, and an independent
determination of the structure of the yeast enzyme has just been completed at 3
A resolution. The conformation of the polypeptide chain is essentially identical
in the two structures, and consists of an inner cylinder of eight strands of
parallel beta-pleated sheet, with mostly helical segments connecting each
strand. The active site is a pocket containing glutamic acid 165, which is
believed to act as a base in the reaction. Crystallographic studies of the
binding of DHAP to both the chicken and the yeast enzymes reveal a common mode
of binding and suggest a mechanisms for catalysis involving polarization of the
substrate carbonyl group.
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