View source for 2xkl


==Crystal Structure of Mouse Apolipoprotein M==
<StructureSection load='2xkl' size='340' side='right'caption='[[2xkl]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2xkl]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Mus_musculus Mus musculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2XKL OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2XKL 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]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=POL:N-PROPANOL'>POL</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=2xkl FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2xkl OCA], [https://pdbe.org/2xkl PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2xkl RCSB], [https://www.ebi.ac.uk/pdbsum/2xkl PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2xkl ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/APOM_MOUSE APOM_MOUSE] Probably involved in lipid transport. Can bind sphingosine-1-phosphate, myristic acid, palmitic acid and stearic acid, retinol, all-trans-retinoic acid and 9-cis-retinoic acid (By similarity).
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Mouse apolipoprotein M (m-apoM) displays a 79% sequence identity to human apolipoprotein M (h-apoM). Both proteins are apolipoproteins associated with high-density lipoproteins, with similar anticipated biological functions. The structure of h-apoM has recently been determined by X-ray crystallography, which revealed that h-apoM displays, as expected, a lipocalin-like fold characterized by an eight-stranded betabarrel that encloses an internal fatty-acid-binding site. Surprisingly, this is not true for m-apoM. After refolding from inclusion bodies, the crystal structure of m-apoM (reported here at 2.5 A resolution) displays a novel yet unprecedented seven-stranded beta-barrel structure. The fold difference is not caused by a mere deletion of a single beta-strand; instead, beta-strands E and F are removed and replaced by a single beta-strand A' formed from residues from the N-terminus. Molecular dynamics simulations suggest that m-apoM is able to adopt both a seven-stranded barrel structure and an eight-stranded barrel structure in solution, and that both folds are comparably stable. Thermal unfolding simulations identify the position where beta-strand exchange occurs as the weak point of the beta-barrel. We wonder whether the switch in topology could have a biological function and could facilitate ligand release, since it goes hand in hand with a narrowing of the barrel diameter. Possibly also, the observed conformation represents an on-pathway or off-pathway folding intermediate of apoM. The difference in fold topology is quite remarkable, and the fold promiscuity observed for m-apoM might possibly provide a glimpse at potential cross-points during the evolution of beta-barrels.

Mouse ApoM displays an unprecedented seven-stranded lipocalin fold: folding decoy or alternative native fold?,Sevvana M, Kassler K, Ahnstrom J, Weiler S, Dahlback B, Sticht H, Muller YA J Mol Biol. 2010 Dec 3;404(3):363-71. Epub 2010 Oct 7. PMID:20932978<ref>PMID:20932978</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Mus musculus]]
[[Category: Dahlback B]]
[[Category: Josefin A]]
[[Category: Kassler K]]
[[Category: Muller YA]]
[[Category: Sevvana M]]
[[Category: Sticht H]]
[[Category: Weiler S]]