View source for 1al3

==COFACTOR BINDING FRAGMENT OF CYSB FROM KLEBSIELLA AEROGENES==
<StructureSection load='1al3' size='340' side='right' caption='[[1al3]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1al3]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AL3 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1AL3 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></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=1al3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1al3 OCA], [http://pdbe.org/1al3 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1al3 RCSB], [http://www.ebi.ac.uk/pdbsum/1al3 PDBsum]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/CYSB_KLEPN CYSB_KLEPN]] This protein is a positive regulator of gene expression for the cysteine regulon. The inducer for CysB is N-acetylserine. Thiosulfate and sulfide act as anti-inducers. 
== 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/al/1al3_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=1al3 ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
BACKGROUND: CysB is a tetrameric protein of identical subunits (M(r) = 36,000) which controls the expression of genes associated with the biosynthesis of cysteine in bacteria. CysB is both an activator and a repressor of transcription whose activity is responsive to the inducer N-acetylserine; thiosulphate and sulphide act as anti-inducers. CysB is a member of the LysR family of prokaryotic transcriptional regulatory proteins which share sequence similarities over approximately 280 residues including a putative helix-turn-helix DNA-binding motif at their N terminus. The aims of the present study were to explore further the complex molecular biology and curious ligand binding properties of CysB and to provide structural insights into the LysR family of proteins. RESULTS: The crystal structure of a dimeric chymotryptic fragment of Klebsiella aerogenes CysB comprising residues 88-324, has been solved by multiple isomorphous replacement and multi-crystal averaging and refined against data extending to 1.8 A resolution. The protein comprises two alpha/beta domains (I and II) connected by two short segments of polypeptide. The two domains enclose a cavity lined by polar sidechains, including those of two residues whose mutation is associated with constitutive expression of the cysteine regulon. A sulphate anion and a number of well ordered water molecules have been modelled into discrete electron-density peaks within this cavity. In the dimer, strands beta B from domain I and strands beta G from domain II come together so that a pair of antiparallel symmetry-related 11-stranded twisted beta-pleated sheets is formed. CONCLUSIONS: The overall structure of CysB(88-324) is strikingly similar to those of the periplasmic substrate-binding proteins. A similar fold has also been observed in the cofactor-binding domain of Lac repressor, implying a structural relationship between the Lac repressor and LysR families of proteins. In contrast to Lac repressor, in CysB the twofold axis of symmetry that relates the monomers in the dimer is perpendicular rather than parallel to the long axis of the cofactor-binding domain. This seems likely to place the DNA-binding domains at opposite extremes of the molecule possibly accounting for CysB's extended DNA footprints.

The structure of the cofactor-binding fragment of the LysR family member, CysB: a familiar fold with a surprising subunit arrangement.,Tyrrell R, Verschueren KH, Dodson EJ, Murshudov GN, Addy C, Wilkinson AJ Structure. 1997 Aug 15;5(8):1017-32. PMID:9309218<ref>PMID:9309218</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1al3" style="background-color:#fffaf0;"></div>

==See Also==
*[[Transcriptional activator|Transcriptional activator]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Tyrrell, R]]
[[Category: Verschueren, K H.G]]
[[Category: Wilkinson, A J]]
[[Category: Cysteine biosynthesis]]
[[Category: Lysr family]]
[[Category: Transcription regulation]]