View source for 3ypi

==ELECTROPHILIC CATALYSIS IN TRIOSEPHOSPHASE ISOMERASE: THE ROLE OF HISTIDINE-95==
<StructureSection load='3ypi' size='340' side='right' caption='[[3ypi]], [[Resolution|resolution]] 2.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3ypi]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3YPI OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3YPI FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=PGH:PHOSPHOGLYCOLOHYDROXAMIC+ACID'>PGH</scene></td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Triose-phosphate_isomerase Triose-phosphate isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.1 5.3.1.1] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3ypi FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ypi OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3ypi RCSB], [http://www.ebi.ac.uk/pdbsum/3ypi PDBsum]</span></td></tr>
</table>
== 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/yp/3ypi_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/chain_selection.php?pdb_ID=2ata ConSurf].
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== Publication Abstract from PubMed ==
Electrophilic catalysis by histidine-95 in triosephosphate isomerase has been probed by using Fourier transform infrared spectroscopy and X-ray crystallography. The carbonyl stretching frequency of dihydroxyacetone phosphate bound to the wild-type enzyme is known to be 19 cm-1 lower (at 1713 cm-1) than that of dihydroxyacetone phosphate free in solution (at 1732 cm-1), and this decrease in stretching frequency has been ascribed to an enzymic electrophile that polarizes the substrate carbonyl group toward the transition state for the enolization. Infrared spectra of substrate bound to two site-directed mutants of yeast triosephosphate isomerase in which histidine-95 has been changed to glutamine or to asparagine show unperturbed carbonyl stretching frequencies between 1732 and 1742 cm-1. The lack of carbonyl polarization when histidine-95 is removed suggests that histidine-95 is indeed the catalytic electrophile, at least for dihydroxyacetone phosphate. Kinetic studies of the glutamine mutant (H95Q) have shown that the enzyme follows a subtly different mechanism of proton transfers involving only a single acid-base catalytic group. These findings suggest an additional role for histidine-95 as a general acid-base catalyst in the wild-type enzyme. The X-ray crystal structure of the H95Q mutant with an intermediate analogue, phosphoglycolohydroxamate, bound at the active site has been solved to 2.8-A resolution, and this structure clearly implicates glutamate-165, the catalytic base in the wild-type isomerase, as the sole acid-base catalyst for the mutant enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophilic catalysis in triosephosphate isomerase: the role of histidine-95.,Komives EA, Chang LC, Lolis E, Tilton RF, Petsko GA, Knowles JR Biochemistry. 1991 Mar 26;30(12):3011-9. PMID:2007138<ref>PMID:2007138</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Triose Phosphate Isomerase|Triose Phosphate Isomerase]]
== References ==
<references/>
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</StructureSection>
[[Category: Saccharomyces cerevisiae]]
[[Category: Triose-phosphate isomerase]]
[[Category: Lolis, E]]
[[Category: Petsko, G A]]