8GRG

Crystal structure of a constitutively active mutant of the alpha gamma heterodimer of human IDH3


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.185 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

Structures of a constitutively active mutant of human IDH3 reveal new insights into the mechanisms of allosteric activation and the catalytic reaction.

Chen, X.Sun, P.Liu, Y.Shen, S.Ma, T.Ding, J.

(2022) J Biol Chem 298: 102695-102695

  • DOI: https://doi.org/10.1016/j.jbc.2022.102695
  • Primary Citation of Related Structures:  
    8GRB, 8GRD, 8GRG, 8GRH, 8GRU, 8GS5

  • PubMed Abstract: 

    Human NAD-dependent isocitrate dehydrogenase or IDH3 (HsIDH3) catalyzes the decarboxylation of isocitrate into α-ketoglutarate in the tricarboxylic acid cycle. It consists of three types of subunits (α, β, and γ) and exists and functions as the (αβαγ) 2 heterooctamer. HsIDH3 is regulated allosterically and/or competitively by numerous metabolites including CIT, ADP, ATP, and NADH. Our previous studies have revealed the molecular basis for the activity and regulation of the αβ and αγ heterodimers. However, the molecular mechanism for the allosteric activation of the HsIDH3 holoenzyme remains elusive. In this work, we report the crystal structures of the αβ and αγ heterodimers and the (αβαγ) 2 heterooctamer containing an α-Q139A mutation in the clasp domain, which renders all the heterodimers and the heterooctamer constitutively active in the absence of activators. Our structural analysis shows that the α-Q139A mutation alters the hydrogen-bonding network at the heterodimer-heterodimer interface in a manner similar to that in the activator-bound αγ heterodimer. This alteration not only stabilizes the active sites of both α Q139A β and α Q139A γ heterodimers in active conformations but also induces conformational changes of the pseudo-allosteric site of the α Q139A β heterodimer enabling it to bind activators. In addition, the α Q139A ICT+Ca+NAD β NAD structure presents the first pseudo-Michaelis complex of HsIDH3, which allows us to identify the key residues involved in the binding of cofactor, substrate, and metal ion. Our structural and biochemical data together reveal new insights into the molecular mechanisms for allosteric regulation and the catalytic reaction of HsIDH3.


  • Organizational Affiliation

    State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Human IDH3 alpha subunit339Homo sapiensMutation(s): 1 
UniProt & NIH Common Fund Data Resources
Find proteins for P50213 (Homo sapiens)
Go to UniProtKB:  P50213
PHAROS:  P50213
GTEx:  ENSG00000166411 
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Isocitrate dehydrogenase [NAD] subunit gamma, mitochondrial354Homo sapiensMutation(s): 0 
Gene Names: IDH3G
UniProt & NIH Common Fund Data Resources
Find proteins for P51553 (Homo sapiens)
Go to UniProtKB:  P51553
PHAROS:  P51553
GTEx:  ENSG00000067829 
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.185 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 137.513α = 90
b = 73.527β = 107.36
c = 86.618γ = 90
Software Package:
Software NamePurpose
HKL-2000data scaling
PHENIXrefinement
PDB_EXTRACTdata extraction
HKL-2000data reduction
PHENIXphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Natural Science Foundation of China (NSFC)China31870723

Revision History  (Full details and data files)

  • Version 1.0: 2022-11-30
    Type: Initial release
  • Version 1.1: 2022-12-21
    Changes: Database references
  • Version 1.2: 2023-11-29
    Changes: Data collection, Refinement description