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| {{STRUCTURE_3blv| PDB=3blv | SCENE= }} | | {{STRUCTURE_3blv| PDB=3blv | SCENE= }} |
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| '''Yeast Isocitrate Dehydrogenase with Citrate Bound in the Regulatory Subunits'''
| | ===Yeast Isocitrate Dehydrogenase with Citrate Bound in the Regulatory Subunits=== |
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| ==Overview==
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| Mitochondrial NAD(+)-specific isocitrate dehydrogenases (IDHs) are key regulators of flux through biosynthetic and oxidative pathways in response to cellular energy levels. Here we present the first structures of a eukaryotic member of this enzyme family, the allosteric, hetero-octameric, NAD(+)-specific IDH from yeast in three forms: 1) without ligands, 2) with bound analog citrate, and 3) with bound citrate + AMP. The structures reveal the molecular basis for ligand binding to homologous but distinct regulatory and catalytic sites positioned at the interfaces between IDH1 and IDH2 subunits and define pathways of communication between heterodimers and heterotetramers in the hetero-octamer. Disulfide bonds observed at the heterotetrameric interfaces in the unliganded IDH hetero-octamer are reduced in the ligand-bound forms, suggesting a redox regulatory mechanism that may be analogous to the "on-off" regulation of non-allosteric bacterial IDHs via phosphorylation. The results strongly suggest that eukaryotic IDH enzymes are exquisitely tuned to ensure that allosteric activation occurs only when concentrations of isocitrate are elevated.
| | The line below this paragraph, {{ABSTRACT_PUBMED_18256028}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 18256028 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_18256028}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Transit peptide]] | | [[Category: Transit peptide]] |
| [[Category: Tricarboxylic acid cycle]] | | [[Category: Tricarboxylic acid cycle]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed May 14 11:40:39 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 07:23:30 2008'' |