View source for 1kt5


==Crystal structure of bovine holo-RBP at pH 4.0==
<StructureSection load='1kt5' size='340' side='right'caption='[[1kt5]], [[Resolution|resolution]] 1.46&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1kt5]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Bos_taurus Bos taurus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KT5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KT5 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]] 1.46&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=RTL:RETINOL'>RTL</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=1kt5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1kt5 OCA], [https://pdbe.org/1kt5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1kt5 RCSB], [https://www.ebi.ac.uk/pdbsum/1kt5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1kt5 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RET4_BOVIN RET4_BOVIN] Delivers retinol from the liver stores to the peripheral tissues. In plasma, the RBP-retinol complex interacts with transthyretin, this prevents its loss by filtration through the kidney glomeruli.
== 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/kt/1kt5_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=1kt5 ConSurf].
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== Publication Abstract from PubMed ==
The targeted delivery of non-polar ligands by binding proteins to membranes or membrane receptors involves the release of these ligands on or near the plasma membrane of target cells. Because these hydrophobic ligands are often bound inside a deep cavity of binding proteins, as shown previously for plasma retinol-binding protein (RBP), their release from these proteins might require the destabilization of the protein structure by partially denaturing conditions, such as those possibly present near plasma membranes. RBP is a plasma transport protein which delivers specifically retinol from its store sites to target cells. Here, we report the high-resolution (1.1-1.4A) crystal structures of bovine holo-RBP at five different pH values, ranging from 9 to 2. While unraveling details of the native protein structure and of the interactions with retinol at nearly atomic resolution at neutral pH, this study provides evidence for definite pH-induced modifications of several structural features of RBP. The structure most representative of the changes that holo-RBP undergoes at different pH values is that of its flexible state at pH 2. At this pH, most significant are the alteration of the arrangement of salt bridges and of the network of water molecules/H-bonds that participates in the retinol-RBP interaction, an appreciable increase of the volume of the beta-barrel cavity, a considerably higher degree of mobility of the RBP-bound ligand and of several protein regions and the disorder of a large number of solvent molecules that are ordered at neutral pH. These changes are likely to be accompanied by a modification of the pattern of charge distribution on the protein surface. All these changes, which reveal a substantially lowered conformational stability of RBP, presumably occur at the initial stages of the acidic denaturation of RBP and are possibly associated with a facilitated release of the retinol molecule from its carrier protein.

High-resolution structures of retinol-binding protein in complex with retinol: pH-induced protein structural changes in the crystal state.,Calderone V, Berni R, Zanotti G J Mol Biol. 2003 Jun 13;329(4):841-50. PMID:12787682<ref>PMID:12787682</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 1kt5" style="background-color:#fffaf0;"></div>

==See Also==
*[[Retinol-binding protein 3D structures|Retinol-binding protein 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bos taurus]]
[[Category: Large Structures]]
[[Category: Berni R]]
[[Category: Calderone V]]
[[Category: Zanotti G]]