1q5m | pdb_00001q5m

Binary complex of rabbit 20alpha-hydroxysteroid dehydrogenase with NADPH

spinqualitylabelsall models 1q5m, resolution 1.32Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1q5m is a 2 chain structure with sequence from European rabbit. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: NDP, SO4 Related: 1q13 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [PE2R_RABIT] Can convert prostaglandin E2 to prostaglandin F2-alpha. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The aldo-keto reductase rabbit 20alpha-hydroxysteroid dehydrogenase (rb20alpha-HSD; AKR1C5) is less selective than other HSDs, since it exerts its activity both on androgens (C19 steroids) and progestins (C21 steroids). In order to identify the molecular determinants responsible for this reduced selectivity, binary (NADPH) and ternary (NADP(+)/testosterone) complex structures were solved to 1.32A and 2.08A resolution, respectively. Inspection of the cofactor-binding cavity led to the identification of a new interaction between side-chains of residues His222 and Lys270, which cover the central phosphate chain of the cofactor, reminiscent of the "safety-belt" found in other aldo-keto reductases. Testosterone is stabilized by a phenol/benzene tunnel composed of side-chains of numerous residues, among which Phe54, which forces the steroid to take up an orientation markedly contrasting with that found in HSD ternary complexes reported. Combining structural, site-directed mutagenesis, kinetic and fluorescence titration studies, we found that the selectivity of rb20alpha-HSD is mediated by (i) the relaxation of loop B (residues 223-230), partly controlled by the nature of residue 230, (ii) the nature of the residue found at position 54, and (iii) the residues found in the C-terminal tail of the protein especially the side-chain of the amino acid 306. Loop relaxation, a mechanism that explains the reduced specificity of rabbit 20alpha-hydroxysteroid dehydrogenase, a member of the aldo-keto reductase superfamily.,Couture JF, Legrand P, Cantin L, Labrie F, Luu-The V, Breton R J Mol Biol. 2004 May 21;339(1):89-102. PMID:15123423 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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