1myk

<StructureSection load='1myk' size='340' side='right' caption='[[1myk]], [[Resolution|resolution]] 2.40&Aring;' scene=''>

<table><tr><td colspan='2'>[[1myk]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Bpp22 Bpp22]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MYK OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1MYK FirstGlance]. <br>

</td></tr><tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">MUTATED ARC GENE ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=10754 BPP22])</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=1myk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1myk OCA], [http://pdbe.org/1myk PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1myk RCSB], [http://www.ebi.ac.uk/pdbsum/1myk PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1myk ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/RARC_BPP22 RARC_BPP22]] This protein acts as a transcriptional repressor of its own gene arc and of gene ant.

Arc repressor is a small, dimeric DNA-binding protein that belongs to the ribbon-helix-helix family of transcription factors. Replacing Pro8 at the N-terminal end of the beta-sheet with leucine increases the stability of the mutant protein by 2.5 kcal/mol of dimer. However, this enhanced stability is achieved at the expense of significantly reduced DNA binding affinity. The structure of the PL8 mutant dimer has been determined to 2.4-A resolution by X-ray crystallography. The overall structure of the mutant is very similar to wild type, but Leu8 makes an additional interstrand hydrogen bond at each end of the beta-sheet of the mutant, increasing the total number of beta-sheet hydrogen bonds from six to eight. Comparison of the refolding and unfolding kinetics of the PL8 mutant and wild-type Arc shows that the enhanced stability of the mutant is accounted for by a decrease in the rate of protein unfolding, suggesting that the mutation acts to stabilize the native state and that the beta-sheet forms after the rate-limiting step in folding. The reduced operator affinity of the PL8 dimer appears to arise because the mutant cannot make the new interstrand hydrogen bonds and simultaneously make the wild-type set of contacts with operator DNA.

 

== References ==

[[Category: Bpp22]]

[[Category: Jeffrey, P D]]

[[Category: Milla, M E]]

[[Category: Raumann, B E]]

[[Category: Sauer, R T]]

[[Category: Schildbach, J F]]

[[Category: Transcription regulation]]