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Cited by 403

The DOI matches its Crossref record; 32 of the 32 references it cites were found in a registry or an index.

Structures of Human Cytosolic NADP-dependent Isocitrate Dehydrogenase Reveal a Novel Self-regulatory Mechanism of Activity

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Xu, Xiang, Zhao, Jingyue, Xu, Zhen, Peng, Baozhen, Huang, Qiuhua, Arnold, Eddy, Ding, Jianping·2004·Journal of Biological Chemistry

Abstract

Isocitrate dehydrogenases (IDHs) catalyze the oxidative decarboxylation of isocitrate to alpha-ketoglutarate, and regulation of the enzymatic activity of IDHs is crucial for their biological functions. Bacterial IDHs are reversibly regulated by phosphorylation of a strictly conserved serine residue at the active site. Eukaryotic NADP-dependent IDHs (NADP-IDHs) have been shown to have diverse important biological functions; however, their regulatory mechanism remains unclear. Structural studies of human cytosolic NADP-IDH (HcIDH) in complex with NADP and in complex with NADP, isocitrate, and Ca2+ reveal three biologically relevant conformational states of the enzyme that differ substantially in the structure of the active site and in the overall structure. A structural segment at the active site that forms a conserved alpha-helix in all known NADP-IDH structures assumes a loop conformation in the open, inactive form of HcIDH; a partially unraveled alpha-helix in the semi-open, intermediate form; and an alpha-helix in the closed, active form. The side chain of Asp279 of this segment occupies the isocitrate-binding site and forms hydrogen bonds with Ser94 (the equivalent of the phosphorylation site in bacterial IDHs) in the inactive form and chelates the metal ion in the active form. The structural data led us to propose a novel self-regulatory mechanism for HcIDH that mimics the phosphorylation mechanism used by the bacterial homologs, consistent with biochemical and biological data. This mechanism might be applicable to other eukaryotic NADP-IDHs. The results also provide insights into the recognition and specificity of substrate and cofactor by eukaryotic NADP-IDHs.

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Metadata

Authors
Xu, X., Zhao, J., Xu, Z., Peng, B., Huang, Q., Arnold, E., & Ding, J.
Venue
Journal of Biological Chemistry
Publisher
Elsevier BV
Published
2004-08
Volume
279
Issue
32
Pages
33946-33957
ISSN
0021-9258 (ISSN-L)
OpenAlex
W2012369631
Cited by
403
References
32
FWCI
3.12
Type
journal article
Language
en
Open access
hybrid

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CoChat. (2026). Citation check: Structures of Human Cytosolic NADP-dependent Isocitrate Dehydrogenase Reveal a Novel Self-regulatory Mechanism of Activity. https://app.cochat.ai/papers/10.1074/jbc.m404298200
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Xu, X., Zhao, J., Xu, Z., Peng, B., Huang, Q., Arnold, E., & Ding, J. (2004). Structures of Human Cytosolic NADP-dependent Isocitrate Dehydrogenase Reveal a Novel Self-regulatory Mechanism of Activity. Journal of Biological Chemistry. https://doi.org/10.1074/jbc.m404298200

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