STEREOSPECIFIC H-1 AND C-13 NMR ASSIGNMENTS OF CROTONYL COA AND HEXADIENOYL COA - CONFORMATIONAL-ANALYSIS AND COMPARISON WITH PROTEIN-COA COMPLEXES

Stereospecific H-1 and C-13 resonance assignments of hexadienoyl-CoA a nd crotonyl-CoA have been determined. The two diastereotopic methyl gr oups at the C2 '' carbon were assigned via transferred nuclear Overhau ser effect experiments on the complex of hexadienoyl-CoA with the enzy me enoyl-CaA hydratase. The two diastereotopic 1 '' protons were assig ned using heteronuclear multiple-bend correlation experiments in conju nction with rotating frame nuclear Overhauser spectroscopy. This repre sents the first set of complete stereospecific assignments for any CoA derivative. The assignments allow a detailed quantitative conformatio nal analysis of the uncomplexed form of the molecule. In particular, t he relative population of the various rotamers about the C1 ''-C2 '' a nd the C2 ''-C3 '' bonds have been determined. The database of protein -bound CoA structures has been surveyed and used to compare the struct ure(s) of CoA in protein-CoA complexes with the conformational prefere nces of free CoA.