1gtu: Difference between revisions
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==LIGAND-FREE HUMAN GLUTATHIONE S-TRANSFERASE M1A-1A== | |||
<StructureSection load='1gtu' size='340' side='right'caption='[[1gtu]], [[Resolution|resolution]] 2.68Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1gtu]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GTU OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1GTU FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.68Å</td></tr> | |||
| | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1gtu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gtu OCA], [https://pdbe.org/1gtu PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1gtu RCSB], [https://www.ebi.ac.uk/pdbsum/1gtu PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1gtu ProSAT]</span></td></tr> | ||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/GSTM1_HUMAN GSTM1_HUMAN] Conjugation of reduced glutathione to a wide number of exogenous and endogenous hydrophobic electrophiles.<ref>PMID:16548513</ref> | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/gt/1gtu_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1gtu ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Domain interchange analyses and site-directed mutagenesis indicate that the His107 residue of the human subunit hGSTM1 has a pronounced influence on catalysis of nucleophilic aromatic substitution reactions, and a H107S substitution accounts for the marked differences in the properties of the homologous hGSTM1-1 (His107) and hGSTM4-4 (Ser107) glutathione S-transferases. Reciprocal replacement of His107 and Ser107 in chimeric enzymes results in reciprocal conversion of catalytic properties. With 1-chloro-2, 4-dinitrobenzene as a substrate, the His107 residue primarily influences the pH dependence of catalysis by lowering the apparent pKa of kcat/Km from 7.8 for the Ser107-containing enzymes to 6.3 for the His107-containing enzymes. There is a parallel shift in the pKa for thiolate anion formation of enzyme-bound GSH. Y6F mutations have no effect on the pKa for these enzymes. Crystal structures of hGSTM1a-1a indicate that the imidazole ring of His107 is oriented toward the substrate binding cleft approximately 6 A from the GSH thiol group. Thus, His107 has the potential to act as a general base in proton transfer mediated through an active site water molecule or directly following a modest conformational change, to promote thiolate anion formation. All wild-type enzymes and H107S chimera have nearly identical equilibrium constants for formation of enzyme-GSH complexes (Kd values of 1-2 x 10(-)6 M); however, KmGSH and Ki values for S-methylglutathione inhibition determined by steady-state kinetics are nearly 100-fold higher. The functions of His107 of hGSTM1a-1a are unexpected in view of a substantial body of previous evidence that excluded participation of histidine residues in the catalytic mechanisms of other glutathione S-transferases. Consequences of His107 involvement in catalysis are also substrate-dependent; in contrast to 1-chloro-2,4-dinitrobenzene, for the nucleophilic addition reaction of GSH to ethacrynic acid, the H107S substitution has no effect on catalysis presumably because product release is rate-limiting. | |||
Functions of His107 in the catalytic mechanism of human glutathione S-transferase hGSTM1a-1a.,Patskovsky YV, Patskovska LN, Listowsky I Biochemistry. 1999 Jan 26;38(4):1193-202. PMID:9930979<ref>PMID:9930979</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1gtu" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[Glutathione S-transferase 3D structures|Glutathione S-transferase 3D structures]] | |||
== References == | |||
== | <references/> | ||
__TOC__ | |||
</StructureSection> | |||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Listowsky | [[Category: Listowsky I]] | ||
[[Category: Patskovska | [[Category: Patskovska LN]] | ||
[[Category: Patskovsky | [[Category: Patskovsky YV]] | ||
Latest revision as of 09:12, 9 August 2023
LIGAND-FREE HUMAN GLUTATHIONE S-TRANSFERASE M1A-1ALIGAND-FREE HUMAN GLUTATHIONE S-TRANSFERASE M1A-1A
Structural highlights
FunctionGSTM1_HUMAN Conjugation of reduced glutathione to a wide number of exogenous and endogenous hydrophobic electrophiles.[1] 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 PubMedDomain interchange analyses and site-directed mutagenesis indicate that the His107 residue of the human subunit hGSTM1 has a pronounced influence on catalysis of nucleophilic aromatic substitution reactions, and a H107S substitution accounts for the marked differences in the properties of the homologous hGSTM1-1 (His107) and hGSTM4-4 (Ser107) glutathione S-transferases. Reciprocal replacement of His107 and Ser107 in chimeric enzymes results in reciprocal conversion of catalytic properties. With 1-chloro-2, 4-dinitrobenzene as a substrate, the His107 residue primarily influences the pH dependence of catalysis by lowering the apparent pKa of kcat/Km from 7.8 for the Ser107-containing enzymes to 6.3 for the His107-containing enzymes. There is a parallel shift in the pKa for thiolate anion formation of enzyme-bound GSH. Y6F mutations have no effect on the pKa for these enzymes. Crystal structures of hGSTM1a-1a indicate that the imidazole ring of His107 is oriented toward the substrate binding cleft approximately 6 A from the GSH thiol group. Thus, His107 has the potential to act as a general base in proton transfer mediated through an active site water molecule or directly following a modest conformational change, to promote thiolate anion formation. All wild-type enzymes and H107S chimera have nearly identical equilibrium constants for formation of enzyme-GSH complexes (Kd values of 1-2 x 10(-)6 M); however, KmGSH and Ki values for S-methylglutathione inhibition determined by steady-state kinetics are nearly 100-fold higher. The functions of His107 of hGSTM1a-1a are unexpected in view of a substantial body of previous evidence that excluded participation of histidine residues in the catalytic mechanisms of other glutathione S-transferases. Consequences of His107 involvement in catalysis are also substrate-dependent; in contrast to 1-chloro-2,4-dinitrobenzene, for the nucleophilic addition reaction of GSH to ethacrynic acid, the H107S substitution has no effect on catalysis presumably because product release is rate-limiting. Functions of His107 in the catalytic mechanism of human glutathione S-transferase hGSTM1a-1a.,Patskovsky YV, Patskovska LN, Listowsky I Biochemistry. 1999 Jan 26;38(4):1193-202. PMID:9930979[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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