2XME

The X-ray structure of CTP:inositol-1-phosphate cytidylyltransferase from Archaeoglobus fulgidus


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.89 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.208 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Crystal Structure of Archaeoglobus Fulgidus Ctp:Inositol-1-Phosphate Cytidylyltransferase, a Key Enzyme for Di-Myo-Inositol-Phosphate Synthesis in (Hyper)Thermophiles.

Brito, J.A.Borges, N.Vonrhein, C.Santos, H.Archer, M.

(2011) J Bacteriol 193: 2177

  • DOI: 10.1128/JB.01543-10
  • Primary Citation of Related Structures:  
    2XME, 2XMH

  • PubMed Abstract: 
  • Many Archaea and Bacteria isolated from hot, marine environments accumulate di-myo-inositol-phosphate (DIP), primarily in response to heat stress. The biosynthesis of this compatible solute involves the activation of inositol to CDP-inositol via the action of a recently discovered CTP:inositol-1-phosphate cytidylyltransferase (IPCT) activity ...

    Many Archaea and Bacteria isolated from hot, marine environments accumulate di-myo-inositol-phosphate (DIP), primarily in response to heat stress. The biosynthesis of this compatible solute involves the activation of inositol to CDP-inositol via the action of a recently discovered CTP:inositol-1-phosphate cytidylyltransferase (IPCT) activity. In most cases, IPCT is part of a bifunctional enzyme comprising two domains: a cytoplasmic domain with IPCT activity and a membrane domain catalyzing the synthesis of di-myo-inositol-1,3'-phosphate-1'-phosphate from CDP-inositol and L-myo-inositol phosphate. Herein, we describe the first X-ray structure of the IPCT domain of the bifunctional enzyme from the hyperthermophilic archaeon Archaeoglobus fulgidus DSMZ 7324. The structure of the enzyme in the apo form was solved to a 1.9-Å resolution. The enzyme exhibited apparent K(m) values of 0.9 and 0.6 mM for inositol-1-phosphate and CTP, respectively. The optimal temperature for catalysis was in the range 90 to 95°C, and the V(max) determined at 90°C was 62.9 μmol · min(-1) · mg of protein(-1). The structure of IPCT is composed of a central seven-stranded mixed β-sheet, of which six β-strands are parallel, surrounded by six α-helices, a fold reminiscent of the dinucleotide-binding Rossmann fold. The enzyme shares structural homology with other pyrophosphorylases showing the canonical motif G-X-G-T-(R/S)-X(4)-P-K. CTP, L-myo-inositol-1-phosphate, and CDP-inositol were docked into the catalytic site, which provided insights into the binding mode and high specificity of the enzyme for CTP. This work is an important step toward the final goal of understanding the full catalytic route for DIP synthesis in the native, bifunctional enzyme.


    Related Citations: 
    • Production, Crystallization and Preliminary X-Ray Analysis of Ctp:Inositol-1-Phosphate Cytidylyltransferase from Archaeoglobus Fulgidus.
      Brito, J.A., Borges, N., Santos, H., Archer, M.
      (2010) Acta Crystallogr Sect F Struct Biol Cryst Commun 66: 1463

    Organizational Affiliation

    Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157 Oeiras, Portugal.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CTP-INOSITOL-1-PHOSPHATE CYTIDYLYLTRANSFERASE
A, B, C, D, E, F, G, H
A, B, C, D, E, F, G, H, I, J, K, L
232Archaeoglobus fulgidusMutation(s): 0 
EC: 2.7.7.74 (UniProt), 2.7.8.34 (UniProt)
Find proteins for O29976 (Archaeoglobus fulgidus (strain ATCC 49558 / VC-16 / DSM 4304 / JCM 9628 / NBRC 100126))
Explore O29976 
Go to UniProtKB:  O29976
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.89 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.206 
  • R-Value Observed: 0.208 
  • Space Group: P 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 86.03α = 90
b = 127.55β = 90.56
c = 141.48γ = 90
Software Package:
Software NamePurpose
BUSTERrefinement
XDSdata reduction
SCALAdata scaling
PHASERphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-05-04
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance