View source for 3da7


==A conformationally strained, circular permutant of barnase==
<StructureSection load='3da7' size='340' side='right' caption='[[3da7]], [[Resolution|resolution]] 2.25&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3da7]] is a 8 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_amyloliquifaciens"_(sic)_fukumoto_1943 "bacillus amyloliquifaciens" (sic) fukumoto 1943] and [http://en.wikipedia.org/wiki/Bacillus_amyloliquefaciens Bacillus amyloliquefaciens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3DA7 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3DA7 FirstGlance]. <br>
</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1brs|1brs]]</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3da7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3da7 OCA], [http://pdbe.org/3da7 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3da7 RCSB], [http://www.ebi.ac.uk/pdbsum/3da7 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3da7 ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/BARS_BACAM BARS_BACAM]] Inhibitor of the ribonuclease barnase. Forms a one-to-one non-covalent complex. 
== 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/da/3da7_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=3da7 ConSurf].
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== Publication Abstract from PubMed ==
Circular permutation of a protein covalently links its original termini and creates new ends at another location. To maintain the stability of the permuted structure, the termini are typically bridged by a peptide long enough to span the original distance between them. Here, we take the opposite approach and employ a very short linker to introduce conformational strain into a protein by forcing its termini together. We join the N- and C-termini of the small ribonuclease barnase (normally 27.2 A distant) with a single Cys residue and introduce new termini at a surface loop, to create pBn. Compared to a similar variant permuted with an 18-residue linker, permutation with a single amino acid dramatically destabilizes barnase. Surprisingly, pBn is folded at 10 degrees C and possesses near wild-type ribonuclease activity. The 2.25 A X-ray crystal structure of pBn reveals how the barnase fold is able to adapt to permutation, partially defuse conformational strain, and preserve enzymatic function. We demonstrate that strain in pBn can be relieved by cleaving the linker with a chemical reagent. Catalytic activity of both uncleaved (strained) pBn and cleaved (relaxed) pBn is proportional to their thermodynamic stabilities, i.e., the fraction of folded molecules. The stability and activity of cleaved pBn are dependent on protein concentration. At concentrations above approximately 2 microM, cleaving pBn is predicted to increase the fraction of folded molecules and thus enhance ribonuclease activity at 37 degrees C. This study suggests that introducing conformational strain by permutation, and releasing strain by cleavage, is a potential mechanism for engineering an artificial zymogen.

Structural and thermodynamic analysis of a conformationally strained circular permutant of barnase.,Butler JS, Mitrea DM, Mitrousis G, Cingolani G, Loh SN Biochemistry. 2009 Apr 21;48(15):3497-507. PMID:19260676<ref>PMID:19260676</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 3da7" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ribonuclease|Ribonuclease]]
*[[Temp|Temp]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bacillus amyloliquefaciens]]
[[Category: Butler, J]]
[[Category: Cingolani, G]]
[[Category: Loh, S N]]
[[Category: Mitrousis, G]]
[[Category: Circular permutant]]
[[Category: Cytoplasm]]
[[Category: Endonuclease]]
[[Category: Protein binding]]
[[Category: Protein-protein complex]]