1E3J image
Deposition Date 2000-06-19
Release Date 2001-02-04
Last Version Date 2024-05-08
Entry Detail
PDB ID:
1E3J
Keywords:
Title:
Ketose reductase (sorbitol dehydrogenase) from silverleaf whitefly
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.30 Å
R-Value Free:
0.25
R-Value Work:
0.21
R-Value Observed:
0.21
Space Group:
I 2 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:NADP(H)-DEPENDENT KETOSE REDUCTASE
Gene (Uniprot):Kr
Chain IDs:A
Chain Length:352
Number of Molecules:1
Biological Source:BEMISIA ARGENTIFOLII
Primary Citation
Crystal Structure of Nadp(H)-Dependent Ketose Reductase from Besimia Argentifolii at 2.3 Angstrom Resolution
J.Mol.Biol. 306 239 ? (2001)
PMID: 11237597 DOI: 10.1006/JMBI.2000.4381

Abstact

Polyhydric alcohols are widely found in nature and can be accumulated to high concentrations as a protection against a variety of environmental stresses. It is only recently, however, that these molecules have been shown to be active in protection against heat stress, specifically in the use of sorbitol by the silverleaf whitefly, Bemisia argentifolii. We have determined the structure of the enzyme responsible for production of sorbitol in Bemisia argentifolii, NADP(H)-dependent ketose reductase (BaKR), to 2.3 A resolution. The structure was solved by multiwavelength anomalous diffraction (MAD) using the anomalous scattering from two zinc atoms bound in the structure, and was refined to an R factor of 21.9 % (R(free)=25.1 %). BaKR belongs to the medium-chain dehydrogenase family and its structure is the first for the sorbitol dehydrogenase branch of this family. The enzyme is tetrameric, with the monomer having a very similar fold to the alcohol dehydrogenases (ADHs). Although the structure determined is for the apo form, a phosphate ion in the active site marks the likely position for the adenyl phosphate of NADP(H). The catalytic zinc ion is tetrahedrally coordinated to Cys41, His66, Glu67 and a water molecule, in a modification of the zinc site usually found in ADHs. This modified zinc site seems likely to be a conserved feature of the sorbitol dehydrogenase sub-family. Comparisons with other members of the ADH family have also enabled us to model a ternary complex of the enzyme, and suggest how structural differences may influence coenzyme binding and substrate specificity in the reduction of fructose to sorbitol.

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