1hld

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spinqualitylabelsall models 1hld, resolution 2.1Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

STRUCTURES OF HORSE LIVER ALCOHOL DEHYDROGENASE COMPLEXED WITH NAD+ AND SUBSTITUTED BENZYL ALCOHOLS

Overview

Structures of the enzyme complexed with NAD+ and, 2,3,4,5,6-pentafluorobenzyl alcohol were determined by X-ray, crystallography at a resolution of 2.1 A and to a refinement R value of, 18.3% for a monoclinic (P2(1)) form and to 2.4 A and an R value of 18.9%, for a triclinic crystal form. The pentafluorobenzyl alcohol does not, react, due to electron withdrawal by the fluorine atoms. A structure with, NAD+ and p-bromobenzyl alcohol in the monoclinic form was also determined, at 2.5 A and an R value of 16.7%. The conformations of the subunits in the, monoclinic and triclinic crystal forms are very similar. The dimer is the, asymmetric unit, and a rigid body rotation closes the cleft between the, coenzyme and catalytic domains upon complex formation. In the monoclinic, form, this conformational change is described by a rotation of 9 degrees, in one subunit and 10 degrees in the other. The pentafluoro- and, p-bromobenzyl alcohols bind in overlapping positions. The hydroxyl group, of each alcohol is ligated to the catalytic zinc and participates in an, extensive hydrogen-bonded network that includes the imidazole group of, His-51, which can act as a base and shuttle a proton to solvent. The, hydroxymethyl carbon of the pentafluorobenzyl alcohol is 3.4 A from C4 of, the nicotinamide ring, and the pro-R hydrogen is in a good position for, direct transfer to C4. The p-bromobenzyl alcohol may react after small, rotations around single bonds of the alcohol. These structures should, approximate the active Michaelis-Menten complexes.

About this Structure

1HLD is a Single protein structure of sequence from Equus caballus with ZN, NAD, PFB and BRB as ligands. Active as Alcohol dehydrogenase, with EC number 1.1.1.1 Full crystallographic information is available from OCA.

Reference

Structures of horse liver alcohol dehydrogenase complexed with NAD+ and substituted benzyl alcohols., Ramaswamy S, Eklund H, Plapp BV, Biochemistry. 1994 May 3;33(17):5230-7. PMID:8172897

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