Flexibility, diversity, and cooperativity: pillars of enzyme catalysis.
This brief review discusses our current understanding of the molecular basis of enzyme catalysis. A historical development is presented, beginning with steady state kinetics and progressing through modern fast reaction methods, nuclear magnetic resonance, and single-molecule fluorescence techniques. Experimental results are summarized for ribonuclease, aspartate aminotransferase, and especially dihydrofolate reductase (DHFR). Multiple intermediates, multiple conformations, and cooperative conformational changes are shown to be an essential part of virtually all enzyme mechanisms. In the case of DHFR, theoretical investigations have provided detailed information about the movement of atoms within the enzyme-substrate complex as the reaction proceeds along the collective reaction coordinate for hydride transfer. A general mechanism is presented for enzyme catalysis that includes multiple intermediates and a complex, multidimensional standard free energy surface. Protein flexibility, diverse protein conformations, and cooperative conformational changes are important features of this model.
Department of Biochemistry, Duke University, Durham, North Carolina 27710, United States.
Gordon G
GG
Hammes
Stephen J
SJ
Benkovic
Sharon
S
Hammes-Schiffer
D001219:Aspartate Aminotransferases / Q000737:chemistry / Q000493:pharmacokinetics; D002384:Catalysis; D004734:Energy Metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000493:pharmacokinetics; D008956:Models, Chemical; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry* / Q000493:pharmacokinetics
D029968:Escherichia coli Proteins; D013762:Tetrahydrofolate Dehydrogenase; D001219:Aspartate Aminotransferases