View source for 1xca


==APO-CELLULAR RETINOIC ACID BINDING PROTEIN II==
<StructureSection load='1xca' size='340' side='right'caption='[[1xca]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1xca]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XCA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1XCA 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]] 2.3&#8491;</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=1xca FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xca OCA], [https://pdbe.org/1xca PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1xca RCSB], [https://www.ebi.ac.uk/pdbsum/1xca PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1xca ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RABP2_HUMAN RABP2_HUMAN] Transports retinoic acid to the nucleus. Regulates the access of retinoic acid to the nuclear retinoic acid receptors.
== 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/xc/1xca_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=1xca ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The crystal structure of unliganded mutant R111M of human cellular retinoic acid-binding protein type II (apo-CRABPII (R111M)) has been determined at 2.3 A and refined to a crystallographic R-factor of 0. 18. Although the mutant protein has lower affinity for all-trans-retinoic acid (RA) than the wild-type, it is properly folded, and its conformation is very similar to the wild-type. apo-CRABPII (R111M) crystallizes in space group P1 with two molecules in the unit cell. The two molecules have high structural similarity except that their alpha2 helices differ strikingly. Analyses of the molecular conformation and crystal packing environment suggest that one of the two molecules assumes a conformation compatible with RA entry. Three structural elements encompassing the opening of the binding pocket exhibit large conformational changes, when compared with holo-CRABPII, which include the alpha2 helix and the betaC-betaD and betaE-betaF hairpin loops. The alpha2 helix is unwound at its N terminus, which appears to be essential for the opening of the RA-binding pocket. Three arginine side-chains (29, 59, and 132) are found with their guanidino groups pointing into the RA-binding pocket. A three-step mechanism of RA entry has been proposed, addressing the opening of the RA entrance, the electrostatic potential that directs entry of RA into the binding pocket, and the intramolecular interactions that stabilize the RA.CRABPII complex via locking the three flexible structural elements when RA is bound.

Crystal structure of apo-cellular retinoic acid-binding protein type II (R111M) suggests a mechanism of ligand entry.,Chen X, Tordova M, Gilliland GL, Wang L, Li Y, Yan H, Ji X J Mol Biol. 1998 May 8;278(3):641-53. PMID:9600845<ref>PMID:9600845</ref>

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

==See Also==
*[[Cellular retinoic acid-binding protein 3D structures|Cellular retinoic acid-binding protein 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Chen X]]
[[Category: Ji X]]