TitleCryo-Electron Microscopy Structures of Yeast Alcohol Dehydrogenase.
Publication TypeJournal Article
Year of Publication2021
AuthorsGuntupalli SRohit, Li Z, Chang L, Plapp BV, Subramanian R
Date Published2021 Mar 09
KeywordsAlcohol Dehydrogenase, Binding Sites, Catalysis, Cryoelectron Microscopy, Crystallography, X-Ray, Models, Molecular, Oxidation-Reduction, Protein Binding, Protein Conformation, Saccharomyces cerevisiae, Substrate Specificity

Structures of yeast alcohol dehydrogenase determined by X-ray crystallography show that the subunits have two different conformational states in each of the two dimers that form the tetramer. Apoenzyme and holoenzyme complexes relevant to the catalytic mechanism were described, but the asymmetry led to questions about the cooperativity of the subunits in catalysis. This study used cryo-electron microscopy (cryo-EM) to provide structures for the apoenzyme, two different binary complexes with NADH, and a ternary complex with NAD and 2,2,2-trifluoroethanol. All four subunits in each of these complexes are identical, as the tetramers have 2 symmetry, suggesting that there is no preexisting asymmetry and that the subunits can be independently active. The apoenzyme and one enzyme-NADH complex have "open" conformations and the inverted coordination of the catalytic zinc with Cys-43, His-66, Glu-67, and Cys-153, whereas another enzyme-NADH complex and the ternary complex have closed conformations with the classical coordination of the zinc with Cys-43, His-66, Cys-153, and a water or the oxygen of trifluoroethanol. The conformational change involves interactions of Arg-340 with the pyrophosphate group of the coenzyme and Glu-67. The cryo-EM and X-ray crystallography studies provide structures relevant for the catalytic mechanism.

Alternate JournalBiochemistry
PubMed ID33620215
Grant ListR01 GM138675 / GM / NIGMS NIH HHS / United States
R01 GM078446 / GM / NIGMS NIH HHS / United States