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| {{STRUCTURE_2gq1| PDB=2gq1 | SCENE= }} | | {{STRUCTURE_2gq1| PDB=2gq1 | SCENE= }} |
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| '''Crystal Structure of Recombinant Type I Fructose-1,6-bisphosphatase from Escherichia coli Complexed with Sulfate Ions'''
| | ===Crystal Structure of Recombinant Type I Fructose-1,6-bisphosphatase from Escherichia coli Complexed with Sulfate Ions=== |
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| ==Overview==
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| 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.
| | The line below this paragraph, {{ABSTRACT_PUBMED_16670087}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 16670087 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_16670087}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Allosteric activator site]] | | [[Category: Allosteric activator site]] |
| [[Category: Quaternary conformation]] | | [[Category: Quaternary conformation]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 05:23:21 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 13:25:57 2008'' |
