2y61

Crystal structure of Leishmanial E65Q-TIM complexed with S-Glycidol phosphate

spinqualitylabelsall models 2y61, resolution 0.99Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2y61 is a 1 chain structure with sequence from Leishmania mexicana. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 0.99Å Ligands: 1GP, G3P, GOL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TPIS_LEIME Publication Abstract from PubMed The key residue of the active site of triosephosphate isomerase (TIM) is the catalytic glutamate, which is proposed to be important (i) as a catalytic base, for initiating the reaction, as well as (ii) for the subsequent proton shuttling steps. The structural properties of this glutamate in the liganded complex have been investigated by studying the high resolution crystal structures of typanosomal TIM, complexed with three suicide inhibitors: (S)-glycidol phosphate ((S)-GOP, at 0.99 A resolution), (R)-glycidol phosphate, ((R)-GOP, at 1.08 A resolution), and bromohydroxyacetone phosphate (BHAP, at 1.97 A resolution). The structures show that in the (S)-GOP active site this catalytic glutamate is in the well characterized, competent conformation. However, an unusual side chain conformation is observed in the (R)-GOP and BHAP complexes. In addition, Glu97, salt bridged to the catalytic lysine in the competent active site, adopts an unusual side chain conformation in these two latter complexes. The higher chemical reactivity of (S)-GOP compared with (R)-GOP, as known from solution studies, can be understood: the structures indicate that in the case of (S)-GOP, Glu167 can attack the terminal carbon of the epoxide in a stereoelectronically favored, nearly linear OCO arrangement, but this is not possible for the (R)-GOP isomer. These structures confirm the previously proposed conformational flexibility of the catalytic glutamate in its closed, liganded state. The importance of this conformational flexibility for the proton shuttling steps in the TIM catalytic cycle, which is apparently achieved by a sliding motion of the side chain carboxylate group above the enediolate plane, is also discussed. High resolution crystal structures of triosephosphate isomerase complexed with its suicide inhibitors: The conformational flexibility of the catalytic glutamate in its closed, liganded active site.,Venkatesan R, Alahuhta M, Pihko PM, Wierenga RK Protein Sci. 2011 Jun 1. doi: 10.1002/pro.667. PMID:21633986 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Triose phosphate isomerase 3D structures

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