Active site electronic structure and dynamics during metalloenzyme catalysis.
Zinc-dependent enzymes play important roles in many cellular processes. Assignment of their reaction mechanisms is often a subject of debate because the zinc ion is silent in several spectroscopic techniques. We have combined time-resolved X-ray absorption spectroscopy, pre-steady state kinetics and computational quantum chemistry to study the active site zinc ion of bacterial alcohol dehydrogenase during single substrate turnover. We detect a series of alternations in the coordination number and structure of the catalytic zinc ion with concomitant changes in metal-ligand bond distances. These structural changes are reflected in the effective charge of the metal ion. The present work emphasizes the flexibility of catalytic zinc sites during catalysis and provides novel mechanistic insights into alcohol dehydrogenase catalysis.
Kleifeld
Oded
O
Department of Structural Biology, The Weizmann Institute of Science, Rehovot 76100, Israel.
Frenkel
Anatoly
A
Martin
Jan M L
JM
Sagi
Irit
I
D000426:Alcohol Dehydrogenase / Q000737:chemistry* / Q000378:metabolism*; D001421:Bacteria, Anaerobic / Q000201:enzymology; D002384:Catalysis; D020134:Catalytic Domain; D007700:Kinetics; D008958:Models, Molecular; D011487:Protein Conformation; D013057:Spectrum Analysis; D055672:Static Electricity; D014965:X-Rays; D015032:Zinc / Q000737:chemistry
D000426:Alcohol Dehydrogenase; D015032:Zinc