Molecule of the Month: Alcohol Dehydrogenase
Alcohol dehydrogenase detoxifies the ethanol we drink
Forms and Functions
Exploring the Structure
Alcohol dehydrogenase uses two molecular "tools" to perform its reaction on ethanol. The first is a zinc atom, which is used to hold and position the alcoholic group on ethanol. The second is a large NAD cofactor (constructed using the vitamin niacin), which actually performs the reaction. PDB entry 1adc , shown here, contains ethanol molecules bound to the two active sites. A slightly-modified version of NAD was used in the structure analysis, so that the enzyme would not immediately attack the ethanol. Notice how the zinc atom is cradled by three amino acids from the protein: cysteine 46 to the left, cysteine 174 to the right, and histidine 67 above. The ethanol binds to the zinc and is positioned next to the NAD cofactor, which extends below the ethanol molecule in this illustration. To explore this structure in more detail, click on the image for an interactive JSmol.
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- 1ykf: Y Korkhin, AJ Kalb(Gilboa), M Peretz, O Bogin, Y Burnstein & F Frolow (1998) NADP-dependent bacterial alcohol dehydrogenases: crystal structure, cofactor-binding and cofactor specificity of the ADHs of Clostridium beijerinickii and Thermoanaerobacter brockii. Journal of Molecular Biology 278, 967-981.
- 1htb: GJ David, WF Bosrun, CL Stone, K Owusu-Dekyi & TD Hurley (1996) X-ray structure of human beta3beta3 alcohol dehydrogenase. Journal of Biological Chemistry 271, 17057-17061.
- 1adc: H Li, WH Hallows, JS Punzi, KW Pankiewicz, KA Watanebe & BM Goldstein (1994) Crystallographic studies of isosteric NAD analogues bound to alcohol dehydrogenase: specificity and substrate binding in two ternary complexes. Biochemistry 33, 11734-11744.
January 2001, David Goodselldoi:10.2210/rcsb_pdb/mom_2001_1