View source for 1sxi

[[Image:1sxi.gif|left|200px]]<br /><applet load="1sxi" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="1sxi, resolution 3.00&Aring;" />
'''Structure of apo transcription regulator B. megaterium'''<br />

==Overview==
Carbon catabolite repression (CCR) is one of the most fundamental environmental-sensing mechanisms in bacteria and imparts competitive advantage by establishing priorities in carbon metabolism. In gram-positive bacteria, the master transcription regulator of CCR is CcpA. CcpA is a LacI-GalR family member that employs, as an allosteric corepressor, the phosphoprotein HPr-Ser46-P, which is formed in glucose-replete conditions. Here we report structures of the Bacillus megaterium apoCcpA and a CcpA-(HPr-Ser46-P)-DNA complex. These structures reveal that HPr-Ser46-P mediates a novel two-component allosteric DNA binding activation mechanism that involves both rotation of the CcpA subdomains and relocation of pivot-point residue Thr61, which leads to juxtaposition of the DNA binding regions permitting "hinge" helix formation in the presence of cognate DNA. The structure of the CcpA-(HPr-Ser46-P)-cre complex also reveals the elegant mechanism by which CcpA family-specific interactions with HPr-Ser46-P residues Ser46-P and His15 partition the high-energy CCR and low-energy PTS pathways, the latter requiring HPr-His15-P.

==About this Structure==
1SXI is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_megaterium Bacillus megaterium] with <scene name='pdbligand=MG:'>MG</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SXI OCA]. 

==Reference==
Structural basis for allosteric control of the transcription regulator CcpA by the phosphoprotein HPr-Ser46-P., Schumacher MA, Allen GS, Diel M, Seidel G, Hillen W, Brennan RG, Cell. 2004 Sep 17;118(6):731-41. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=15369672 15369672]
[[Category: Bacillus megaterium]]
[[Category: Single protein]]
[[Category: Allen, G S.]]
[[Category: Brennan, R G.]]
[[Category: Diel, M.]]
[[Category: Hillen, W.]]
[[Category: Schumacher, M A.]]
[[Category: Seidel, G.]]
[[Category: MG]]
[[Category: allosterism; phosphoprotein; transcription regulation; gram positive bacteria; ccr]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:06:37 2008''