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).