View source for 3kih


==The crystal structures of two fragments truncated from 5-bladed beta-propeller lectin, tachylectin-2 (Lib2-D2-15)==
<StructureSection load='3kih' size='340' side='right'caption='[[3kih]], [[Resolution|resolution]] 2.49&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3kih]] is a 5 chain structure with sequence from [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3KIH OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3KIH 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]] 2.49&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GDL:2-ACETAMIDO-2-DEOXY-D-GLUCONO-1,5-LACTONE'>GDL</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=3kih FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3kih OCA], [https://pdbe.org/3kih PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3kih RCSB], [https://www.ebi.ac.uk/pdbsum/3kih PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3kih ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TAL2_TACTR TAL2_TACTR] Lectin that binds specifically to N-acetylglucosamine and N-acetylgalactosamine. Is part of the innate immunity host defense system of the horseshoe crab.
== 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/ki/3kih_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=3kih ConSurf].
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== Publication Abstract from PubMed ==
The primary sequence of proteins usually dictates a single tertiary and quaternary structure. However, certain proteins undergo reversible backbone rearrangements. Such metamorphic proteins provide a means of facilitating the evolution of new folds and architectures. However, because natural folds emerged at the early stages of evolution, the potential role of metamorphic intermediates in mediating evolutionary transitions of structure remains largely unexplored. We evolved a set of new proteins based on approximately 100 amino acid fragments derived from tachylectin-2--a monomeric, 236 amino acids, five-bladed beta-propeller. Their structures reveal a unique pentameric assembly and novel beta-propeller structures. Although identical in sequence, the oligomeric subunits adopt two, or even three, different structures that together enable the pentameric assembly of two propellers connected via a small linker. Most of the subunits adopt a wild-type-like structure within individual five-bladed propellers. However, the bridging subunits exhibit domain swaps and asymmetric strand exchanges that allow them to complete the two propellers and connect them. Thus, the modular and metamorphic nature of these subunits enabled dramatic changes in tertiary and quaternary structure, while maintaining the lectin function. These oligomers therefore comprise putative intermediates via which beta-propellers can evolve from smaller elements. Our data also suggest that the ability of one sequence to equilibrate between different structures can be evolutionary optimized, thus facilitating the emergence of new structures.

Metamorphic proteins mediate evolutionary transitions of structure.,Yadid I, Kirshenbaum N, Sharon M, Dym O, Tawfik DS Proc Natl Acad Sci U S A. 2010 Apr 20;107(16):7287-92. Epub 2010 Apr 5. PMID:20368465<ref>PMID:20368465</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 3kih" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Dym O]]
[[Category: Tawfik DS]]
[[Category: Yadid I]]