2gq1
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(New page: 200px<br /><applet load="2gq1" size="450" color="white" frame="true" align="right" spinBox="true" caption="2gq1, resolution 1.450Å" /> '''Crystal Structure o...)
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Revision as of 09:12, 21 November 2007
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Crystal Structure of Recombinant Type I Fructose-1,6-bisphosphatase from Escherichia coli Complexed with Sulfate Ions
Overview
Fructose-1,6-bisphosphatase (FBPase) governs a key step in, gluconeogenesis, the conversion of fructose 1,6-bisphosphate into fructose, 6-phosphate. In mammals, the enzyme is subject to metabolic regulation, but regulatory mechanisms of bacterial FBPases are not well understood., Presented here is the crystal structure (resolution, 1.45A) of recombinant, FBPase from Escherichia coli, the first structure of a prokaryotic Type I, FBPase. The E. coli enzyme is a homotetramer, but in a quaternary state, between the canonical R- and T-states of porcine FBPase. Phe(15) and, residues at the C-terminal side of the first alpha-helix (helix H1) occupy, the AMP binding pocket. Residues at the N-terminal side of helix H1, hydrogen bond with sulfate ions buried at a subunit interface, which in, porcine FBPase undergoes significant conformational change in response to, allosteric effectors. Phosphoenolpyruvate and sulfate activate E. coli, FBPase by at least 300%. Key residues that bind sulfate anions are, conserved among many heterotrophic bacteria, but are absent in FBPases of, organisms that employ fructose 2,6-bisphosphate as a regulator. These, observations suggest a new mechanism of regulation in the FBPase enzyme, family: anionic ligands, most likely phosphoenolpyruvate, bind to, allosteric activator sites, which in turn stabilize a tetramer and a, polypeptide fold that obstructs AMP binding.
About this Structure
2GQ1 is a Single protein structure of sequence from Escherichia coli with SO4 as ligand. Active as Fructose-bisphosphatase, with EC number 3.1.3.11 Full crystallographic information is available from OCA.
Reference
Novel allosteric activation site in Escherichia coli fructose-1,6-bisphosphatase., Hines JK, Fromm HJ, Honzatko RB, J Biol Chem. 2006 Jul 7;281(27):18386-93. Epub 2006 May 2. PMID:16670087
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