4icg: Difference between revisions
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==N-terminal dimerization domain of H-NS in complex with Hha (Salmonella Typhimurium)== | |||
===N-terminal dimerization domain of H-NS in complex with | <StructureSection load='4icg' size='340' side='right' caption='[[4icg]], [[Resolution|resolution]] 2.92Å' scene=''> | ||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4icg]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Salmonella_enterica_subsp._enterica_serovar_typhimurium_str._uk-1 Salmonella enterica subsp. enterica serovar typhimurium str. uk-1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4ICG OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4ICG FirstGlance]. <br> | |||
</td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene></td></tr> | |||
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">hns, STMUK_1724 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=990282 Salmonella enterica subsp. enterica serovar Typhimurium str. UK-1]), hha, STMUK_0480 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=990282 Salmonella enterica subsp. enterica serovar Typhimurium str. UK-1])</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=4icg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4icg OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4icg RCSB], [http://www.ebi.ac.uk/pdbsum/4icg PDBsum]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The bacterial nucleoid associated proteins Hha and H-NS jointly repress horizontally acquired genes in Salmonella, including essential virulence loci encoded within Salmonella pathogenicity islands. Hha is known to interact with the N-terminal dimerization domain of H-NS, however the manner in which this interaction enhances transcriptional silencing is not understood. To further understand this process we solved the X-ray crystal structure of Hha in complex with the N-terminal dimerization domain of H-NS (H-NS1-46) to 3.2 A resolution. Two monomers of Hha bind to symmetrical sites on either side of the H-NS1-46 dimer. Disruption of the Hha/H-NS interaction by the H-NS site-specific mutation I11A, results in increased expression of the Hha/H-NS co-regulated gene hilA without affecting the expression levels of proV, a target gene repressed by H-NS in an Hha-independent fashion. Examination of the structure revealed a cluster of conserved basic amino acids that protrude from the surface of Hha on the opposite side of the Hha/H-NS1-46 interface. Hha mutants with a diminished positively charged surface maintain the ability to interact with H-NS but can no longer regulate hilA. Increased expression of the hilA locus did not correspond to significant depletion of H-NS at the promoter region in chromatin immunoprecipitation assays. However in vitro, we find Hha improves H-NS binding to target DNA fragments. Taken together, our results show for the first time how Hha and H-NS interact to direct transcriptional repression and reveal that a positively charged surface of Hha enhances the silencing activity of H-NS nucleoprotein filaments. | |||
Structural Insights into the Regulation of Foreign Genes in Salmonella by the Hha/H-NS Complex.,Ali SS, Whitney JC, Stevenson J, Robinson H, Howell PL, Navarre WW J Biol Chem. 2013 Mar 20. PMID:23515315<ref>PMID:23515315</ref> | |||
== | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
</div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Salmonella enterica subsp. enterica serovar typhimurium str. uk-1]] | [[Category: Salmonella enterica subsp. enterica serovar typhimurium str. uk-1]] | ||
[[Category: Ali, S S | [[Category: Ali, S S]] | ||
[[Category: Howell, P L | [[Category: Howell, P L]] | ||
[[Category: Navarre, W W | [[Category: Navarre, W W]] | ||
[[Category: Robinson, H | [[Category: Robinson, H]] | ||
[[Category: Stevenson, J | [[Category: Stevenson, J]] | ||
[[Category: Whitney, J C | [[Category: Whitney, J C]] | ||
[[Category: Dna binding protein]] | [[Category: Dna binding protein]] | ||
[[Category: Hha]] | [[Category: Hha]] | ||
