Structure of Pseudomonas aeruginosa Isocitrate Dehydrogenase, IDH

Experimental Data Snapshot

  • Resolution: 2.71 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.211 

Starting Model: experimental
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Gluconeogenic precursor availability regulates flux through the glyoxylate shunt inPseudomonas aeruginosa.

Crousilles, A.Dolan, S.K.Brear, P.Chirgadze, D.Y.Welch, M.

(2018) J Biol Chem 293: 14260-14269

  • DOI: https://doi.org/10.1074/jbc.RA118.004514
  • Primary Citation of Related Structures:  
    5M2E, 6G1O, 6G3U

  • PubMed Abstract: 

    The glyoxylate shunt bypasses the oxidative decarboxylation steps of the tricarboxylic acid (TCA) cycle, thereby conserving carbon skeletons for gluconeogenesis and biomass production. In Escherichia coli , carbon flux is redirected through the first enzyme of the glyoxylate shunt, isocitrate lyase (ICL), following phosphorylation and inactivation of the TCA cycle enzyme, isocitrate dehydrogenase (ICD), by the kinase/phosphatase, AceK. In contrast, mycobacterial species lack AceK and employ a phosphorylation-insensitive isocitrate dehydrogenase (IDH), which is allosterically activated by the product of ICL activity, glyoxylate. However, Pseudomonas aeruginosa expresses IDH, ICD, ICL, and AceK, raising the question of how these enzymes are regulated to ensure proper flux distribution between the competing pathways. Here, we present the structure, kinetics, and regulation of ICL, IDH, and ICD from P. aeruginosa We found that flux partitioning is coordinated through reciprocal regulation of these enzymes, linking distribution of carbon flux to the availability of the key gluconeogenic precursors, oxaloacetate and pyruvate. Specifically, a greater abundance of these metabolites activated IDH and inhibited ICL, leading to increased TCA cycle flux. Regulation was also exerted through AceK-dependent phosphorylation of ICD; high levels of acetyl-CoA (which would be expected to accumulate when oxaloacetate is limiting) stimulated the kinase activity of AceK, whereas high levels of oxaloacetate stimulated its phosphatase activity. In summary, the TCA cycle-glyoxylate shunt branch point in P. aeruginosa has a complex enzymology that is profoundly different from those in other species characterized to date. Presumably, this reflects its predilection for consuming fatty acids, especially during infection scenarios.

  • Organizational Affiliation

    From the Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, United Kingdom.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Isocitrate dehydrogenase
A, B
737Pseudomonas aeruginosaMutation(s): 0 
Gene Names: idhPA2624
Find proteins for Q9I0L4 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Explore Q9I0L4 
Go to UniProtKB:  Q9I0L4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9I0L4
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on NAP

Download Ideal Coordinates CCD File 
C21 H28 N7 O17 P3
Query on AKG

Download Ideal Coordinates CCD File 
C5 H6 O5
Experimental Data & Validation

Experimental Data

  • Resolution: 2.71 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.211 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 126.46α = 90
b = 149.02β = 90
c = 201.137γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
PDB_EXTRACTdata extraction

Structure Validation

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Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Biotechnology and Biological Sciences Research CouncilUnited Kingdom--

Revision History  (Full details and data files)

  • Version 1.0: 2018-08-01
    Type: Initial release
  • Version 1.1: 2018-08-29
    Changes: Data collection, Database references
  • Version 1.2: 2018-09-26
    Changes: Data collection, Database references
  • Version 1.3: 2024-01-17
    Changes: Data collection, Database references, Refinement description