4KGX

The R state structure of E. coli ATCase with CTP bound


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.192 
  • R-Value Work: 0.156 
  • R-Value Observed: 0.158 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

New Paradigm for Allosteric Regulation of Escherichia coli Aspartate Transcarbamoylase.

Cockrell, G.M.Zheng, Y.Guo, W.Peterson, A.W.Truong, J.K.Kantrowitz, E.R.

(2013) Biochemistry 52: 8036-8047

  • DOI: 10.1021/bi401205n
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • For nearly 60 years, the ATP activation and the CTP inhibition of Escherichia coli aspartate transcarbamoylase (ATCase) has been the textbook example of allosteric regulation. We present kinetic data and five X-ray structures determined in the absenc ...

    For nearly 60 years, the ATP activation and the CTP inhibition of Escherichia coli aspartate transcarbamoylase (ATCase) has been the textbook example of allosteric regulation. We present kinetic data and five X-ray structures determined in the absence and presence of a Mg(2+) concentration within the physiological range. In the presence of 2 mM divalent cations (Mg(2+), Ca(2+), Zn(2+)), CTP does not significantly inhibit the enzyme, while the allosteric activation by ATP is enhanced. The data suggest that the actual allosteric inhibitor of ATCase in vivo is the combination of CTP, UTP, and a divalent cation, and the actual allosteric activator is a divalent cation with ATP or ATP and GTP. The structural data reveals that two NTPs can bind to each allosteric site with a divalent cation acting as a bridge between the triphosphates. Thus, the regulation of ATCase is far more complex than previously believed and calls many previous studies into question. The X-ray structures reveal that the catalytic chains undergo essentially no alternations; however, several regions of the regulatory chains undergo significant structural changes. Most significant is that the N-terminal region of the regulatory chains exists in different conformations in the allosterically activated and inhibited forms of the enzyme. Here, a new model of allosteric regulation is proposed.


    Organizational Affiliation

    Department of Chemistry, Boston College , Merkert Chemistry Center, 2609 Beacon Street, Chestnut Hill, MA 02467 U.S.A.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Aspartate carbamoyltransferase
A, C
310Escherichia coli KO11FLMutation(s): 0 
Gene Names: pyrBEKO11_4066KO11_22860
EC: 2.1.3.2
Protein Feature View is not available: No corresponding UniProt sequence found.

Find similar proteins by: Sequence  |  Structure

Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Aspartate carbamoyltransferase regulatory chain
B, D
153Escherichia coli KO11FLMutation(s): 0 
Gene Names: pyrIEKO11_4067KO11_22855
EC: 2.1.3.2
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CTP
Query on CTP

Download CCD File 
B, D
CYTIDINE-5'-TRIPHOSPHATE
C9 H16 N3 O14 P3
PCDQPRRSZKQHHS-XVFCMESISA-N
 Ligand Interaction
PAL
Query on PAL

Download CCD File 
A, C
N-(PHOSPHONACETYL)-L-ASPARTIC ACID
C6 H10 N O8 P
ZZKNRXZVGOYGJT-VKHMYHEASA-N
 Ligand Interaction
ZN
Query on ZN

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.192 
  • R-Value Work: 0.156 
  • R-Value Observed: 0.158 
  • Space Group: P 3 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 121.237α = 90
b = 121.237β = 90
c = 154.772γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling
PHENIXphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-11-27
    Type: Initial release
  • Version 1.1: 2017-11-15
    Changes: Refinement description