2c8u: Difference between revisions
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==Overview== | ==Overview== | ||
During turnover, the catalytic tyrosine residue (Tyr10) of the sigma class, Schistosoma haematobium wild-type glutathione-S-transferase is expected to, switch alternately in and out of the reduced glutathione-binding site, (G-site). The Tyrout10 conformer forms a pi-cation interaction with the, guanidinium group of Arg21. As in other similar, glutathione-S-transferases, the catalytic Tyr has a low pKa of 7.2. In, order to investigate the catalytic role of Tyr10, and the structural and, functional roles of Arg21, we carried out structural studies on two Arg21, mutants (R21L and R21Q) and a Tyr10 mutant, Y10F. Our crystallographic, data for the two Arg21 mutants indicate that only the Tyrout10, conformation is populated, thereby excluding a role of Arg21 in the, stabilisation of the out ... | During turnover, the catalytic tyrosine residue (Tyr10) of the sigma class, Schistosoma haematobium wild-type glutathione-S-transferase is expected to, switch alternately in and out of the reduced glutathione-binding site, (G-site). The Tyrout10 conformer forms a pi-cation interaction with the, guanidinium group of Arg21. As in other similar, glutathione-S-transferases, the catalytic Tyr has a low pKa of 7.2. In, order to investigate the catalytic role of Tyr10, and the structural and, functional roles of Arg21, we carried out structural studies on two Arg21, mutants (R21L and R21Q) and a Tyr10 mutant, Y10F. Our crystallographic, data for the two Arg21 mutants indicate that only the Tyrout10, conformation is populated, thereby excluding a role of Arg21 in the, stabilisation of the out conformation. However, Arg21 was confirmed to be, catalytically important and essential for the low pKa of Tyr10. Upon, comparison with structural data generated for reduced glutathione-bound, and inhibitor-bound wild-type enzymes, it was observed that the, orientations of Tyr10 and Arg35 are concerted and that, upon ligand, binding, minor rearrangements occur within conserved residues in the, active site loop. These rearrangements are coupled to quaternary, rigid-body movements at the dimer interface and alterations in the, localisation and structural order of the C-terminal domain. | ||
==About this Structure== | ==About this Structure== | ||
2C8U is a | 2C8U is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Schistosoma_haematobium Schistosoma haematobium] with SO4 and BME as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Glutathione_transferase Glutathione transferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.5.1.18 2.5.1.18] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2C8U OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 15:25:33 2007'' | ||
