5gri

Crystal structure of the alpha gamma heterodimer of human IDH3 in complex with Mg(2+) and citrate

spinqualitylabelsall models 5gri, resolution 2.31Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5gri is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.31Å Ligands: CIT, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function IDH3A_HUMAN Publication Abstract from PubMed Human NAD-dependent isocitrate dehydrogenase catalyzes the decarboxylation of isocitrate (ICT) into alpha-ketoglutarate in the Krebs cycle. It exists as the alpha2betagamma heterotetramer composed of the alphabeta and alphagamma heterodimers. Previously, we have demonstrated biochemically that the alpha2betagamma heterotetramer and alphagamma heterodimer can be allosterically activated by citrate (CIT) and ADP. In this work, we report the crystal structures of the alphagamma heterodimer with the gamma subunit bound without or with different activators. Structural analyses show that CIT, ADP and Mg2+ bind adjacent to each other at the allosteric site. The CIT binding induces conformational changes at the allosteric site, which are transmitted to the active site through the heterodimer interface, leading to stabilization of the ICT binding at the active site and thus activation of the enzyme. The ADP binding induces no further conformational changes but enhances the CIT binding through Mg2+-mediated interactions, yielding a synergistic activation effect. ICT can also bind to the CIT-binding subsite, which induces similar conformational changes but exhibits a weaker activation effect. The functional roles of the key residues are verified by mutagenesis, kinetic and structural studies. Our structural and functional data together reveal the molecular mechanism of the allosteric regulation of the alphagamma heterodimer. Molecular mechanism of the allosteric regulation of the alphagamma heterodimer of human NAD-dependent isocitrate dehydrogenase.,Ma T, Peng Y, Huang W, Ding J Sci Rep. 2017 Jan 18;7:40921. doi: 10.1038/srep40921. PMID:28098230 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Isocitrate dehydrogenase 3D structures

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