View source for 1bqa


==ASPARTATE AMINOTRANSFERASE P195A MUTANT==
<StructureSection load='1bqa' size='340' side='right'caption='[[1bqa]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1bqa]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BQA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1BQA 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]] 2.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=LLP:(2S)-2-AMINO-6-[[3-HYDROXY-2-METHYL-5-(PHOSPHONOOXYMETHYL)PYRIDIN-4-YL]METHYLIDENEAMINO]HEXANOIC+ACID'>LLP</scene></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=1bqa FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1bqa OCA], [https://pdbe.org/1bqa PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1bqa RCSB], [https://www.ebi.ac.uk/pdbsum/1bqa PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1bqa ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/AAT_ECOLI AAT_ECOLI] 
== 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/bq/1bqa_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=1bqa ConSurf].
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== Publication Abstract from PubMed ==
To elucidate the role of the two conserved cis-proline residues of aspartate aminotransferase (AspAT), one double and two single mutants of the enzyme from Escherichia coli (EcAspAT) were prepared: P138A, P195A and P138A/P195A in which the two prolines were replaced by alanine. The crystal structures of P195A and P138A/P195A have been determined at 2.3-2.1 A resolution. The wild-type geometry, including the cis conformation of the 194-195 peptide bond is retained upon substitution of proline 195 by alanine, whereas the trans conformation is adopted at the 137-138 peptide bond. Quite surprisingly, the replacement of each of the two prolines by alanine does not significantly affect either the activity or the stability of the protein. All the three mutants follow the same pathway as the wild type for unfolding equilibrium induced by guanidine hydrochloride [Herold, M., and Kirschner, K. (1990) Biochemistry 29, 1907-1913]. The kinetics of renaturation of P195A, where the alanine retains the wild-type cis conformation, is faster than wild type, whereas renaturation of P138A, which adopts the trans conformation, is slower. We conclude that cis-prolines seem to have been retained throughout the evolution of aspartate aminotransferase to possibly play a subtle role in directing the traffic of intermediates toward the unique structure of the native state, rather than to respond to the needs for a specific catalytic or functional role.

Functional and structural analysis of cis-proline mutants of Escherichia coli aspartate aminotransferase.,Birolo L, Malashkevich VN, Capitani G, De Luca F, Moretta A, Jansonius JN, Marino G Biochemistry. 1999 Jan 19;38(3):905-13. PMID:9893985<ref>PMID:9893985</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1bqa" style="background-color:#fffaf0;"></div>

==See Also==
*[[Aspartate aminotransferase 3D structures|Aspartate aminotransferase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Jansonius JN]]
[[Category: Malashkevich VN]]