View source for 1a72

==AN ACTIVE-SITE DOUBLE MUTANT (PHE93->TRP, VAL203->ALA) OF HORSE LIVER ALCOHOL DEHYDROGENASE IN COMPLEX WITH THE ISOSTERIC NAD ANALOG CPAD==
<StructureSection load='1a72' size='340' side='right' caption='[[1a72]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1a72]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Equus_caballus Equus caballus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A72 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1A72 FirstGlance]. <br>
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=PAD:5-BETA-D-RIBOFURANOSYLPICOLINAMIDE+ADENINE-DINUCLEOTIDE'>PAD</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene><br>
<tr><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">F93W V203ALADH ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9796 Equus caballus])</td></tr>
<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Alcohol_dehydrogenase Alcohol dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.1 1.1.1.1] </span></td></tr>
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1a72 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1a72 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1a72 RCSB], [http://www.ebi.ac.uk/pdbsum/1a72 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/a7/1a72_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].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The oxidation of alcohol to aldehyde by horse liver alcohol dehydrogenase (LADH) requires the transfer of a hydride ion from the alcohol substrate to the cofactor nicotinamide adenine dinucleotide (NAD). A quantum mechanical tunneling contribution to this hydride transfer step has been demonstrated in a number of LADH mutants designed to enhance or diminish this effect [Bahnson, B. J., et al. (1997) Proc. Natl. Acad. Sci. U.S.A. 94, 12797-12802]. The active site double mutant Phe93 --&gt; Trp/Val203 --&gt; Ala shows a 75-fold reduction in catalytic efficiency relative to that of the native enzyme, and reduced tunneling relative to that of either single mutant. We present here two crystal structures of the double mutant: a 2.0 A complex with NAD and the substrate analogue trifluoroethanol and a 2.6 A complex with the isosteric NAD analogue CPAD and ethanol. Changes at the active site observed in both complexes are consistent with reduced activity and tunneling. The NAD-trifluoroethanol complex crystallizes in the closed conformation characteristic of the active enzyme. However, the NAD nicotinamide ring rotates away from the substrate, toward the space vacated by replacement of Val203 with the smaller alanine. Replacement of Phe93 with the larger tryptophan also produces unfavorable steric contacts with the nicotinamide carboxamide group, potentially destabilizing hydrogen bonds required to maintain the closed conformation. These contacts are relieved in the second complex by rotation of the CPAD pyridine ring into an unusual syn orientation. The resulting loss of the carboxamide hydrogen bonds produces an open conformation characteristic of the apoenzyme.

Active site modifications in a double mutant of liver alcohol dehydrogenase: structural studies of two enzyme-ligand complexes.,Colby TD, Bahnson BJ, Chin JK, Klinman JP, Goldstein BM Biochemistry. 1998 Jun 30;37(26):9295-304. PMID:9649310<ref>PMID:9649310</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>

==See Also==
*[[Alcohol dehydrogenase|Alcohol dehydrogenase]]
*[[Horse Liver Alcohol Dehydrogenase|Horse Liver Alcohol Dehydrogenase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Alcohol dehydrogenase]]
[[Category: Equus caballus]]
[[Category: Bahnson, B J.]]
[[Category: Chin, J K.]]
[[Category: Colby, T D.]]
[[Category: Goldstein, B M.]]
[[Category: Klinman, J P.]]
[[Category: Active site mutant]]
[[Category: Isosteric nad inhibitor]]
[[Category: Liver alcohol dehydrogenase]]
[[Category: Oxidoreductase]]