Tetrameric NAD-dependent alcohol dehydrogenase.

Three-dimensional structures of the ethanol-induced, tetrameric alcohol dehydrogenase from Escherichia coli have recently been determined in the absence and presence of NAD. The structure of the E. coli enzyme is similar to those of the dimeric mammalian alcohol dehydrogenases, but it has a deletion of 21 residues located at the surface of the catalytic domain. The catalytic zinc ions have two different types of coordination, which are also observed in the class III dimeric mammalian alcohol dehydrogenase. Comparison of the structures provide new insights into the relationship between tetrameric and dimeric alcohol dehydrogenases and provide a link to the structure of the tetrameric yeast alcohol dehydrogenase.