View source for 1qka


==OLIGO-PEPTIDE BINDING PROTEIN (OPPA) COMPLEXED WITH KRK==
<StructureSection load='1qka' size='340' side='right'caption='[[1qka]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1qka]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Salmonella_enterica_subsp._enterica_serovar_Typhimurium Salmonella enterica subsp. enterica serovar Typhimurium] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QKA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1QKA 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]] 1.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=IUM:URANYL+(VI)+ION'>IUM</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=1qka FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1qka OCA], [https://pdbe.org/1qka PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1qka RCSB], [https://www.ebi.ac.uk/pdbsum/1qka PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1qka ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/OPPA_SALTY OPPA_SALTY] This protein is a component of the oligopeptide permease, a binding protein-dependent transport system, it binds peptides up to five amino acids long with high affinity.
== 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/qk/1qka_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1qka ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Isothermal titration calorimetry has been used to study the binding of 20 different peptides to the peptide binding protein OppA, and the crystal structures of the ligand complexes have been refined. This periplasmic binding protein, part of the oligopeptide permease system of Gram negative bacteria, has evolved to bind and enclose small peptides of widely varying sequences. The peptides used in this study have the sequence Lys-X-Lys, where X is any of the 20 commonly occurring amino acids. The various side-chains found at position 2 on the ligand fit into a hydrated pocket. The majority of side-chains are restrained to particular conformations within the pocket. Water molecules act as flexible adapters, matching the hydrogen-bonding requirements of the protein and ligand and shielding charges on the buried ligand. This use of water by OppA to broaden the repertoire of its binding site is not unique, but contrasts sharply with other proteins which use water to help bind ligands highly selectively. Predicting the thermodynamics of binding from the structure of the complexes is highly complicated by the influence of water on the system.

Crystallographic and calorimetric analysis of peptide binding to OppA protein.,Sleigh SH, Seavers PR, Wilkinson AJ, Ladbury JE, Tame JR J Mol Biol. 1999 Aug 13;291(2):393-415. PMID:10438628<ref>PMID:10438628</ref>

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

==See Also==
*[[ABC transporter 3D structures|ABC transporter 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Salmonella enterica subsp. enterica serovar Typhimurium]]
[[Category: Synthetic construct]]
[[Category: Tame JRH]]
[[Category: Wilkinson AJ]]