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R M Garavito

Publications and source records attributed to R M Garavito.

60 records · Page 4Linked to original sources
PubMed1977

Convergence of active center geometries.

Comparisons have been made between the active center geometries of lactate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase, chymotrypsin and papain, and glyceraldehyde-3-phosphate dehydrogenase and papain. In the dehydrogenases, orientation of the nicotinamide ring about the glycosidic bond is determined by the substrate stereochemistry. The proper positioning of the carboxyamide moiety allows for the close approach of the C4 atom on the nicotinamide and the reactive carbon of the substrate. It follows that, once the conformation of the substrate or substrate intermediate has been established with respect to the functional groups in the enzyme, the A- or B-side specificity of the nicotinamide ring is predetermined. Hence, dehydrogenases which are divergently evolving from a common precursor must maintain the nicotinamide specificity if the protein fold of the catalytic domain is conserved. The tetrahedral intermediates produced during acylation of chymotrypsin and papain are found to be of opposite hand, while those of papain and glyceraldehyde-3-phosphate dehydrogenase can be regarded to be of the same hand. Thus the serine proteases, subtilisin and those of the chymotrypsin family, are of one hand while the cysteine enzymes, glyceraldehyde-3-phosphate dehydrogenase and papain, are of the other.

Binding Sites↗
PubMed1977

Molecular asymmetry in an abortive ternary complex of lobster glyceraldehyde-3-phosphate dehydrogenase.

An abortive ternary complex of lobster glyceraldehyde-3-phosphate dehydrogenase was produced by the covalent attachment of 3,3,3-trifluoroacetone to Cys- 149 in each subunit. X-ray diffraction analysis of the glyceraldehyde-3-phosphate dehydrogenase-trifluoroacetone-nicotinamide adenine dinucleotide complex showed asymmetry with respect to the active-site conformations of the trifluoroacetone substrate analogue and some catalytic groups. These results are consistent with 19F nuclear magnetic resonance observations of this complex (Bode, J., Blumenstein, M., and Raftery, M. A. (1975), Biochemistry 14, 1153--1160). Different substrate conformations were found on opposite sides of the molecular diad relating subunits whose active centers are in close proximity (the R axis).

Animals↗