1PG5

CRYSTAL STRUCTURE OF THE UNLIGATED (T-STATE) ASPARTATE TRANSCARBAMOYLASE FROM THE EXTREMELY THERMOPHILIC ARCHAEON SULFOLOBUS ACIDOCALDARIUS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.195 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Crystal Structure of T State Aspartate Carbamoyltransferase of the Hyperthermophilic Archaeon Sulfolobus acidocaldarius.

De Vos, D.Van Petegem, F.Remaut, H.Legrain, C.Glansdorff, N.Van Beeumen, J.J.

(2004) J Mol Biol 339: 887-900

  • DOI: 10.1016/j.jmb.2004.03.079
  • Primary Citation of Related Structures:  
    1PG5

  • PubMed Abstract: 
  • Aspartate carbamoyltransferase (ATCase) is a model enzyme for understanding allosteric effects. The dodecameric complex exists in two main states (T and R) that differ substantially in their quaternary structure and their affinity for various ligands ...

    Aspartate carbamoyltransferase (ATCase) is a model enzyme for understanding allosteric effects. The dodecameric complex exists in two main states (T and R) that differ substantially in their quaternary structure and their affinity for various ligands. Many hypotheses have resulted from the structure of the Escherichia coli ATCase, but so far other crystal structures to test these have been lacking. Here, we present the tertiary and quaternary structure of the T state ATCase of the hyperthermophilic archaeon Sulfolobus acidocaldarius (SaATC(T)), determined by X-ray crystallography to 2.6A resolution. The quaternary structure differs from the E.coli ATCase, by having altered interfaces between the catalytic (C) and regulatory (R) subunits, and the presence of a novel C1-R2 type interface. Conformational differences in the 240 s loop region of the C chain and the C-terminal region of the R chain affect intersubunit and interdomain interfaces implicated previously in the allosteric behavior of E.coli ATCase. The allosteric-zinc binding domain interface is strengthened at the expense of a weakened R1-C4 type interface. The increased hydrophobicity of the C1-R1 type interface may stabilize the quaternary structure. Catalytic trimers of the S.acidocaldarius ATCase are unstable due to a drastic weakening of the C1-C2 interface. The hyperthermophilic ATCase presents an interesting example of how an allosteric enzyme can adapt to higher temperatures. The structural rearrangement of this thermophilic ATCase may well promote its thermal stability at the expense of changes in the allosteric behavior.


    Organizational Affiliation

    Laboratorium voor Eiwitbiochemie en Eiwitengineering, Universiteit Gent, Ghent, Belgium.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Aspartate carbamoyltransferaseA299Sulfolobus acidocaldariusMutation(s): 0 
Gene Names: pyrB
EC: 2.1.3.2
Find proteins for Q55338 (Sulfolobus acidocaldarius (strain ATCC 33909 / DSM 639 / JCM 8929 / NBRC 15157 / NCIMB 11770))
Explore Q55338 
Go to UniProtKB:  Q55338
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Aspartate carbamoyltransferase regulatory chainB168Sulfolobus acidocaldariusMutation(s): 0 
Gene Names: pyrI
Find proteins for P74766 (Sulfolobus acidocaldarius (strain ATCC 33909 / DSM 639 / JCM 8929 / NBRC 15157 / NCIMB 11770))
Explore P74766 
Go to UniProtKB:  P74766
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download CCD File 
B
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.195 
  • Space Group: P 63 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 132.853α = 90
b = 132.853β = 90
c = 140.279γ = 120
Software Package:
Software NamePurpose
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-06-08
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Derived calculations, Version format compliance