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Three-dimensional structure of d-glyceraldehyde-3-phosphate dehydrogenase

1974; Elsevier BV; Volume: 90; Issue: 1 Linguagem: Inglês

10.1016/0022-2836(74)90254-x

1089-8638

Manfred Buehner, Geoffrey C. Ford, Dino Moras, Kenneth W. Olsen, Michael G. Rossmann,

Metabolism and Genetic Disorders

The crystal structure of lobster d-glyceraldehyde-3-phosphate dehydrogenase has been analyzed. A 3.0 Å resolution electron density map of an averaged subunit showed that: (1) The subunit structure consists of two domains. The first (residues 1 to 149) is essentially the coenzyme binding fold whereas the second (residues 150 to 334) provides residues for catalysis, specificity and subunit-subunit co-operativity. (2) The first domain is similar to structures found in other dehydrogenases and kinases. Some of the important residues involved in binding the coenzyme, NAD+, are the same in d-glyceraldehyde-3-phosphate dehydrogenase as in lactate dehydrogenase. (3) The conformation of NAD+ is essentially the same in d-glyceraldehyde-3-phosphate dehydrogenase as in lactate dehydrogenase, apart from a 180 ° rotation about the ribose-nicotinamide glycosidic bond, thus exposing the B side of the nicotinamide ring to the substrate. (4) The second domain contains histidine 176 situated near the essential cysteine 149 and presumably acting as a base during catalysis. (5) Lysine 183 binds to the pyrophosphate in the active site of the adjacent subunit, creating the unique situation in which the catalytic center contains residues from two different subunits. Thus the NAD binding sites are directly linked in pairs by virtue of a molecular 2-fold axis, forming a functional dimer. The co-operativity (positive in yeast and negative in muscle enzyme) and the half-of-the-sites reaction properties are probably associated with this characteristic. (6) The position of the two sulfate anion sites suggests the position of binding of the substrate phosphate and the inorganic phosphate to be subsequently incorporated into the product. (7) The amino acids in the active center region and involved in subunit-subunit contacts are more highly conserved than other residues.