2cax: Difference between revisions
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[[ | ==STRUCTURAL BASIS FOR COOPERATIVE BINDING OF RIBBON-HELIX-HELIX REPRESSOR OMEGA TO MUTATED DIRECT DNA HEPTAD REPEATS== | ||
<StructureSection load='2cax' size='340' side='right' caption='[[2cax]], [[Resolution|resolution]] 2.90Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[2cax]] is a 8 chain structure with sequence from [http://en.wikipedia.org/wiki/Streptococcus_pyogenes Streptococcus pyogenes]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2CAX OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2CAX FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1irq|1irq]], [[2bnw|2bnw]], [[2bnz|2bnz]]</td></tr> | |||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2cax FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2cax OCA], [http://www.rcsb.org/pdb/explore.do?structureId=2cax RCSB], [http://www.ebi.ac.uk/pdbsum/2cax PDBsum]</span></td></tr> | |||
<table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Repressor omega regulates transcription of genes required for copy number control, accurate segregation and stable maintenance of inc18 plasmids hosted by Gram-positive bacteria. omega belongs to homodimeric ribbon-helix-helix (RHH2) repressors typified by a central, antiparallel beta-sheet for DNA major groove binding. Homodimeric omega2 binds cooperatively to promotors with 7 to 10 consecutive non-palindromic DNA heptad repeats (5'-(A)/(T)ATCAC(A)/(T)-3', symbolized by -->) in palindromic inverted, converging (--><--) or diverging (<---->) orientation and also, unique to omega2 and contrasting other RHH2 repressors, to non-palindromic direct (-->-->) repeats. Here we investigate with crystal structures how omega2 binds specifically to heptads in minimal operators with (-->-->) and (--><--) repeats. Since the pseudo-2-fold axis relating the monomers in omega(2) passes the central C-G base pair of each heptad with approximately 0.3 A downstream offset, the separation between the pseudo-2-fold axes is exactly 7 bp in (-->-->), approximately 0.6 A shorter in (--><--) but would be approximately 0.6 A longer in (<---->). These variations grade interactions between adjacent omega2 and explain modulations in cooperative binding affinity of omega2 to operators with different heptad orientations. | |||
Structures of omega repressors bound to direct and inverted DNA repeats explain modulation of transcription.,Weihofen WA, Cicek A, Pratto F, Alonso JC, Saenger W Nucleic Acids Res. 2006 Mar 9;34(5):1450-8. Print 2006. PMID:16528102<ref>PMID:16528102</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
== | |||
< | |||
[[Category: Streptococcus pyogenes]] | [[Category: Streptococcus pyogenes]] | ||
[[Category: Alonso, J C.]] | [[Category: Alonso, J C.]] | ||
Revision as of 06:53, 9 June 2014
STRUCTURAL BASIS FOR COOPERATIVE BINDING OF RIBBON-HELIX-HELIX REPRESSOR OMEGA TO MUTATED DIRECT DNA HEPTAD REPEATS
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