1EZZ

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.182 

wwPDB Validation 3D Report Full Report


This is version 1.2 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

  • Primary Citation of Related Structures:  

  • 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  • The only cis-proline residue in Escherichia coli aspartate transcarbamoylase has been replaced by alanine using site-specific mutagenesis.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 ...

    The only cis-proline residue in Escherichia coli aspartate transcarbamoylase has been replaced by alanine using site-specific mutagenesis.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

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ASPARTATE CARBAMOYLTRANSFERASE CATALYTIC CHAIN
A, C
310Escherichia coli (strain K12)Mutation(s): 1 
Gene Names: pyrB
EC: 2.1.3.2
Find proteins for P0A786 (Escherichia coli (strain K12))
Go to UniProtKB:  P0A786
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
ASPARTATE CARBAMOYLTRANSFERASE REGULATORY CHAIN
B, D
153Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: pyrI
Find proteins for P0A7F3 (Escherichia coli (strain K12))
Go to UniProtKB:  P0A7F3
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.182 
  • Space Group: H 3
Unit Cell:
Length (Å)Angle (°)
a = 129.870α = 90.00
b = 129.870β = 90.00
c = 198.340γ = 120.00
Software Package:
Software NamePurpose
SDMSdata reduction
X-PLORrefinement
AMoREphasing
SDMSdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-11-22
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance