1EZZ

CRYSTAL STRUCTURE OF E. COLI ASPARTATE TRANSCARBAMOYLASE P268A MUTANT IN THE T-STATE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.182 

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This is version 1.3 of the entry. See complete history


Literature

A cis-proline to alanine mutant of E. coli aspartate transcarbamoylase: kinetic studies and three-dimensional crystal structures.

Jin, L.Stec, B.Kantrowitz, E.R.

(2000) Biochemistry 39: 8058-8066

  • DOI: 10.1021/bi000418+
  • Primary Citation of Related Structures:  
    1EZZ, 1F1B

  • PubMed Abstract: 
  • The only cis-proline residue in Escherichia coli aspartate transcarbamoylase has been replaced by alanine using site-specific mutagenesis. The Pro268-->Ala enzyme exhibits a 40-fold reduction in enzyme activity and decreased substrate affinity toward carbamoyl phosphate and aspartate compared to the corresponding values for the wild-type enzyme ...

    The only cis-proline residue in Escherichia coli aspartate transcarbamoylase has been replaced by alanine using site-specific mutagenesis. The Pro268-->Ala enzyme exhibits a 40-fold reduction in enzyme activity and decreased substrate affinity toward carbamoyl phosphate and aspartate compared to the corresponding values for the wild-type enzyme. The concentration of the bisubstrate analogue N-phosphonacetyl-L-aspartate (PALA) required to activate the mutant enzyme to the same extent as the wild-type enzyme is significantly increased. The heterotropic effects of ATP and CTP upon the Pro268-->Ala enzyme are also altered. Crystal structures of the Pro268-->Ala enzyme in both T- and R-states show that the cis-peptidyl linkage between Leu267 and Ala268 is maintained. However, the tertiary structure of both the catalytic and regulatory chains has been altered by the amino acid substitution, and the mobility of the active-site residues is increased for the R-state structure of Pro268-->Ala enzyme as comparison with the wild-type R-state structure. These structural changes are responsible for the loss of enzyme activity. Thus, Pro268 is required for the proper positioning of catalytically critical residues in the active site and is important for the formation of the high-activity high-affinity R-state of E. coli aspartate transcarbamoylase.


    Related Citations: 
    • Structural Consequences of Effector Binding to the T State of Aspartate Carbamoyltransferase: Crystal Structures of the Unligated and ATP- and CTP-complexed enzymes at 2.6-A resolution
      Stevens, R.C., Gouaux, J.E., Lipscomb, W.N.
      (1990) Biochemistry 29: 7691

    Organizational Affiliation

    Department of Chemistry, Boston College, Merkert Chemistry Center, Chestnut Hill, Massachusetts 02467, USA.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
ASPARTATE CARBAMOYLTRANSFERASE CATALYTIC CHAINA, C310Escherichia coliMutation(s): 1 
EC: 2.1.3.2
UniProt
Find proteins for P0A786 (Escherichia coli (strain K12))
Explore P0A786 
Go to UniProtKB:  P0A786
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A786
Protein Feature View
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  • Reference Sequence
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
ASPARTATE CARBAMOYLTRANSFERASE REGULATORY CHAINB, D153Escherichia coliMutation(s): 0 
UniProt
Find proteins for P0A7F3 (Escherichia coli (strain K12))
Explore P0A7F3 
Go to UniProtKB:  P0A7F3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A7F3
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 Ideal Coordinates CCD File 
E [auth B],
F [auth D]
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.182 
  • Space Group: H 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 129.87α = 90
b = 129.87β = 90
c = 198.34γ = 120
Software Package:
Software NamePurpose
AMoREphasing
X-PLORrefinement
SDMSdata reduction
SDMSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-11-22
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-11-03
    Changes: Database references, Derived calculations