4jeq

Different Contribution of Conserved Amino Acids to the Global Properties of Homologous Enzymes

spinqualitylabelsall models 4jeq, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4jeq is a 12 chain structure with sequence from Trypanosoma cruzi. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.303Å Ligands: PEG, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TPIS_TRYBB Publication Abstract from PubMed It is generally assumed that the amino acids that exist in all homologous enzymes correspond to residues that participate in catalysis, or that are essential for folding and stability. Although this holds for catalytic residues, the function of conserved non-catalytic residues is not clear. It is not known if such residues are of equal importance and have the same role in different homologous enzymes. In humans, the E104D mutation in triosephosphate isomerase (TIM) is the most frequent mutation in the autosomal diseases named "TPI deficiencies". We explored if the E104D mutation has the same impact in TIMs from four different organisms (Homo sapiens, Giardia lamblia, Trypanosoma cruzi, T. brucei). The catalytic properties were not significantly affected by the mutation, but it affected the rate and extent of formation of active dimers from unfolded monomers differently. Scanning calorimetry experiments indicated that the mutation was in all cases destabilizing, but the mutation effect on rates of irreversible denaturation and transition-state energetics were drastically dependent on the TIM background. For instance, mutational changes in activation energy ranged from 430 kJ mol-1 in HsTIM to -78 kJ mol-1 in TcTIM. Thus, in TIM the role of a conserved non-catalytic residue is drastically dependent on its molecular background. Accordingly, it would seem that because each protein has a particular sequence, and a distinctive set of amino acid interactions, it should be regarded as a unique entity that has evolved for function and stability in the organisms to which it belongs. (c) Proteins 2013;. (c) 2013 Wiley Periodicals, Inc. Different contribution of conserved amino acids to the global properties of Triosephosphate isomerases.,Aguirre Y, Cabrera N, Aguirre B, Perez-Montfort R, Hernandez-Santoyo A, Reyes-Vivas H, Enriquez-Flores S, de Gomez-Puyou MT, Gomez-Puyou A, Sanchez-Ruiz JM, Costas M Proteins. 2013 Aug 22. doi: 10.1002/prot.24398. PMID:23966267 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Triose phosphate isomerase 3D structures

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