1glc: Difference between revisions

[[Image:1glc.jpg|left|200px]]<br /><applet load="1glc" size="350" color="white" frame="true" align="right" spinBox="true"  

A central question in molecular biology concerns the means by which a regulatory protein recognizes different targets. IIIGlc, the glucose-specific phosphocarrier protein of the bacterial phosphotransferase system, is also the central regulatory element of the PTS. Binding of unphosphorylated IIIGlc inhibits several non-PTS proteins, but there is little or no sequence similarity between IIIGlc binding sites on different target proteins. The crystal structure of Escherichia coli IIIGlc bound to one of its regulatory targets, glycerol kinase, has been refined at 2.6-A resolution in the presence of products, adenosine diphosphate and glycerol 3-phosphate. Structural and kinetic analyses show that the complex of IIIGlc with glycerol kinase creates an intermolecular Zn(II) binding site with ligation identical to that of the zinc peptidase thermolysin. The zinc is coordinated by the two active-site histidines of IIIGlc, a glutamate of glycerol kinase, and a water molecule. Zn(II) at 0.01 and 0.1 mM decreases the Ki of IIIGlc for glycerol kinase by factors of about 15 and 60, respectively. The phosphorylation of one of the histidines of IIIGlc, in its alternative role as phosphocarrier, provides an elegant means of controlling the cation-enhanced protein-protein regulatory interaction. The need for the target protein to supply only one metal ligand may account for the lack of sequence similarity among the regulatory targets of IIIGlc.

1GLC is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=MG:'>MG</scene>, <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=G3H:'>G3H</scene> and <scene name='pdbligand=ADP:'>ADP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Protein-N(pi)-phosphohistidine--sugar_phosphotransferase Protein-N(pi)-phosphohistidine--sugar phosphotransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.69 2.7.1.69] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GLC OCA].  

[[Category: Feese, M D.]]

[[Category: Meadow, N D.]]

[[Category: Pettigrew, D W.]]

[[Category: Remington, S J.]]

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