1lde
HORSE LIVER ALCOHOL DEHYDROGENASE COMPLEXED TO NADH AND N-FORMYL PIPERDINE
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OverviewOverview
Amides are analogs of aldehydes and potent inhibitors of liver alcohol, dehydrogenases. They can be used for structural studies and for inhibiting, the metabolism of alcohols that form toxic products. We studied N-alkyl, amides that bind to the enzyme-NADH complex and act as uncompetitive, inhibitors against varied concentrations of ethanol (millimolar Kii, values, at pH 8 and 25 degrees C): N-propylacetamide (16), delta-valerolactam (1.6), N-formylpiperidine (0.14), N-isobutylformamide, (0.028), N-(cyclohexylmethyl)-formamide (0.011), and N-cyclohexylformamide, (0.0087). The lower affinity of delta-valerolactam and N-propylacetamide, can be explained by steric hindrance with Phe93 of the enzyme. Replacing, Phe93 with Ala in the S48T/F93A mutated enzyme, which resembles the, natural alpha-isoenzyme of primates, improved binding of, delta-valerolactam by 210-fold. The structures of horse liver enzyme, complexed with NADH and N-cyclohexylformamide or N-formylpiperidine were, determined by X-ray crystallography at 2.5 A resolution. In both, complexes, the carbonyl oxygens of the inhibitors bind to the catalytic, zinc and form a hydrogen bond to the hydroxyl group of Ser48 of the, enzyme. The six-membered rings bind in overlapping, but rotated, positions, that optimize hydrophobic interactions. The binding modes of the, unreactive formamides appear to resemble the Michaelis complexes of the, analogous substrates, with the re face of the carbonyl carbon suitably, positioned to accept a hydrogen from NADH.
About this StructureAbout this Structure
1LDE is a Single protein structure of sequence from Equus caballus with ZN, NAD and FPI as ligands. Active as Alcohol dehydrogenase, with EC number 1.1.1.1 Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
Binding of formamides to liver alcohol dehydrogenase., Ramaswamy S, Scholze M, Plapp BV, Biochemistry. 1997 Mar 25;36(12):3522-7. PMID:9132002
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