19F nuclear magnetic resonance studies of structure and function relations in trifluoroacetonylated rabbit muscle glyceraldehyde-3-phosphate dehydrogenase
- 25 March 1975
- journal article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 14 (6) , 1153-1160
- https://doi.org/10.1021/bi00677a009
Abstract
Specific reaction of Cys-149 with 3,3,3-trifluorobromacetone allows one to probe symmetry relation between the active center regions of tetrameric glyceraldehyde-3-phosphate dehydrogenase by 19F nuclear magnetic resonance (nmr) techniques. Nmr titration studies in the pH range of greatest enzymic activity reveal the existence of species with an (alphaalpha')2 structure; this symmetry is not induced by the coenzyme. Addition of NADH to the ketone-labeled protein causes the enzymic reduction of the ligand in a stereospecific manner and is used to demonstrate the functionality of residues other than Cys-149 that are essential for catalysis. The interpretation of chemical shift characteristics found for the trifluoroacetonyl group together with the kinetics of its reduction allows the derivation of a dynamic model for the enzymic structure which may contribute to understanding of the half-of-the-sites phenomenon.Keywords
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