View source for 4qfv


==Crystal structure of a unique ankyrin==
<StructureSection load='4qfv' size='340' side='right'caption='[[4qfv]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4qfv]] is a 4 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=4QFV OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4QFV 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]] 1.999&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</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=4qfv FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4qfv OCA], [https://pdbe.org/4qfv PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4qfv RCSB], [https://www.ebi.ac.uk/pdbsum/4qfv PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4qfv ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
A highly diverse DNA library coding for ankyrin seven-repeat proteins (ANK-N5C) was designed and constructed by a PCR-based combinatorial assembly strategy. A bacterial melibiose fermentation assay was adapted for in vivo functional screen. We isolated a transcription blocker that completely inhibits the melibiose-dependent expression of alpha-galactosidase (MelA) and melibiose permease (MelB) of Escherichia coli by specifically preventing activation of the melAB operon. High-resolution crystal structural determination reveals that the designed ANK-N5C protein has a typical ankyrin fold, and the specific transcription blocker, ANK-N5C-281, forms a domain-swapped dimer. Functional tests suggest that the activity of MelR, a DNA-binding transcription activator and a member of AraC family of transcription factors, is inhibited by ANK-N5C-281 protein. All ANK-N5C proteins are expected to have a concave binding area with negative surface potential, suggesting that the designed ANK-N5C library proteins may facilitate the discovery of binders recognizing structural motifs with positive surface potential, like in DNA-binding proteins. Overall, our results show that the established library is a useful tool for the discovery of novel bioactive reagents.

A transcription blocker isolated from a designed repeat protein combinatorial library by in vivo functional screen.,Tikhonova EB, Ethayathulla AS, Su Y, Hariharan P, Xie S, Guan L Sci Rep. 2015 Jan 28;5:8070. doi: 10.1038/srep08070. PMID:25627011<ref>PMID:25627011</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4qfv" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Ethayathulla AS]]
[[Category: Guan L]]
[[Category: Tikhonova EB]]