View source for 1xki


==Crystal structure of human tear lipocalin/von Ebners gland protein==
<StructureSection load='1xki' size='340' side='right'caption='[[1xki]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1xki]] is a 1 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=1XKI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1XKI 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=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=1xki FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xki OCA], [https://pdbe.org/1xki PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1xki RCSB], [https://www.ebi.ac.uk/pdbsum/1xki PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1xki ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/LCN1_HUMAN LCN1_HUMAN] Could play a role in taste reception. Could be necessary for the concentration and delivery of sapid molecules in the gustatory system. Can bind various ligands, with chemical structures ranging from lipids and retinoids to the macrocyclic antibiotic rifampicin and even to microbial siderophores. Exhibits an extremely wide ligand pocket.
== 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/xk/1xki_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=1xki ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
In contrast with earlier assumptions, which classified human tear lipocalin (Tlc) as an outlier member of the lipocalin protein family, the 1.8-A resolution crystal structure of the recombinant apoprotein confirms the typical eight-stranded antiparallel beta-barrel architecture with an alpha-helix attached to it. The fold of Tlc most closely resembles the bovine dander allergen Bos d 2, a well characterized prototypic lipocalin, but also reveals similarity with beta-lactoglobulin. However, compared with other lipocalin structures Tlc exhibits an extremely wide ligand pocket, whose entrance is formed by four partially disordered loops. The cavity deeply extends into the beta-barrel structure, where it ends in two distinct lobes. This unusual structural feature explains the known promiscuity of Tlc for various ligands, with chemical structures ranging from lipids and retinoids to the macrocyclic antibiotic rifampin and even to microbial siderophores. Notably, earlier findings of biological activity as a thiol protease inhibitor have no correspondence in the three-dimensional structure of Tlc, rather it appears that its proteolytic fragments could be responsible for this phenomenon. Hence, the present structural analysis sheds new light on the ligand binding activity of this functionally obscure but abundant human lipocalin.

The 1.8-A crystal structure of human tear lipocalin reveals an extended branched cavity with capacity for multiple ligands.,Breustedt DA, Korndorfer IP, Redl B, Skerra A J Biol Chem. 2005 Jan 7;280(1):484-93. Epub 2004 Oct 15. PMID:15489503<ref>PMID:15489503</ref>

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

==See Also==
*[[Neutrophil gelatinase-associated lipocalin|Neutrophil gelatinase-associated lipocalin]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Breustedt DA]]
[[Category: Korndoerfer IP]]
[[Category: Redl B]]
[[Category: Skerra A]]