PDBsum entry: 1e3j

Oxidoreductase

PDB id: 1e3j

Contents

Protein chain

348 a.a. *

Ligands

PO4

BO3

Metals

_ZN ×2

Waters ×47

* Residue conservation analysis

PDB id:

1e3j

Name:

Oxidoreductase

Title:

Ketose reductase (sorbitol dehydrogenase) from silverleaf whitefly

Structure:

NADP(h)-dependent ketose reductase. Chain: a. Engineered: yes

Source:

Bemisia argentifolii. Silverleaf whitefly. Organism_taxid: 77855. Expressed in: escherichia coli. Expression_system_taxid: 562

Biol. unit:

Homo-Tetramer (from PDB file)

Resolution:

2.3Å R-factor: 0.219 R-free: 0.250

Authors:

M.J.Banfield,M.E.Salvucci,E.N.Baker,C.A.Smith

Key ref:

M.J.Banfield et al. (2001). Crystal structure of the NADP(H)-dependent ketose reductase from Bemisia argentifolii at 2.3 A resolution. J Mol Biol, 306, 239-250. PubMed id: 11237597 DOI: 10.1006/jmbi.2000.4381

Date:

19-Jun-00 Release date: 04-Feb-01

Protein chain

O96496  (O96496_BEMAR) -  NADP(H)-dependent ketose reductase

Seq: 352 a.a.

Struc: 348 a.a.

 Gene Ontology (GO) functional annotation 

• Biological process: oxidation-reduction process (1 term)
• Biochemical function: nucleotide binding (4 terms)

DOI no: 10.1006/jmbi.2000.4381

J Mol Biol 306:239-250 (2001)

PubMed id: 11237597

Crystal structure of the NADP(H)-dependent ketose reductase from Bemisia argentifolii at 2.3 A resolution.

M.J.Banfield, M.E.Salvucci, E.N.Baker, C.A.Smith.

ABSTRACT

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.

Selected figure(s)

Figure 2.
Figure 2. Stereoviews showing examples of (a) the experimental MAD/DM electron density map used to build the initial model, and (b) the final weighted 2|F[obs]| -|F[calc]|.f[calc] electron density map. Both maps are contoured at 1.1s, and cover residues 171-188. The Figure was prepared with BOBSCRIPT[45] and Raster3D. [46]

Figure 3.
Figure 3. (a) Stereoview of the C^a trace of the final BaKR model, with the N, C termini, and every tenth amino acid residue labelled. (b) Schematic view of the secondary structure arrangement in BaKR. The two zinc atoms bound in the structure are shown in green. Figure prepared with MOLSCRIPT[47] and Raster3D. [46]

The above figures are reprinted by permission from Elsevier: J Mol Biol (2001, 306, 239-250) copyright 2001.

Figures were selected by an automated process.