View source for 2jab


==A designed ankyrin repeat protein evolved to picomolar affinity to Her2==
<StructureSection load='2jab' size='340' side='right'caption='[[2jab]], [[Resolution|resolution]] 1.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2jab]] is a 3 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=2JAB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2JAB 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]] 1.7&#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=2jab FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2jab OCA], [https://pdbe.org/2jab PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2jab RCSB], [https://www.ebi.ac.uk/pdbsum/2jab PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2jab ProSAT]</span></td></tr>
</table>
== 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/ja/2jab_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=2jab ConSurf].
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== Publication Abstract from PubMed ==
Designed ankyrin repeat proteins (DARPins) are a novel class of binding molecules, which can be selected to recognize specifically a wide variety of target proteins. DARPins were previously selected against human epidermal growth factor receptor 2 (Her2) with low nanomolar affinities. We describe here their affinity maturation by error-prone PCR and ribosome display yielding clones with zero to seven (average 2.5) amino acid substitutions in framework positions. The DARPin with highest affinity (90 pM) carried four mutations at framework positions, leading to a 3000-fold affinity increase compared to the consensus framework variant, mainly coming from a 500-fold increase of the on-rate. This DARPin was found to be highly sensitive in detecting Her2 in human carcinoma extracts. We have determined the crystal structure of this DARPin at 1.7 A, and found that a His to Tyr mutation at the framework position 52 alters the inter-repeat H-bonding pattern and causes a significant conformational change in the relative disposition of the repeat subdomains. These changes are thought to be the reason for the enhanced on-rate of the mutated DARPin. The DARPin not bearing the residue 52 mutation has an unusually slow on-rate, suggesting that binding occurred via conformational selection of a relatively rare state, which was stabilized by this His52Tyr mutation, increasing the on-rate again to typical values. An analysis of the structural location of the framework mutations suggests that randomization of some framework residues either by error-prone PCR or by design in a future library could increase affinities and the target binding spectrum.

A designed ankyrin repeat protein evolved to picomolar affinity to Her2.,Zahnd C, Wyler E, Schwenk JM, Steiner D, Lawrence MC, McKern NM, Pecorari F, Ward CW, Joos TO, Pluckthun A J Mol Biol. 2007 Jun 15;369(4):1015-28. Epub 2007 Mar 20. PMID:17466328<ref>PMID:17466328</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 2jab" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Joos TO]]
[[Category: Lawrence MC]]
[[Category: McKern NM]]
[[Category: Pecorari F]]
[[Category: Pluckthun A]]
[[Category: Schwenk JM]]
[[Category: Steiner D]]
[[Category: Ward CW]]
[[Category: Wyler E]]
[[Category: Zahnd C]]