1D09

ASPARTATE TRANSCARBAMOYLASE COMPLEXED WITH N-PHOSPHONACETYL-L-ASPARTATE (PALA)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.203 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Insights into the mechanisms of catalysis and heterotropic regulation of Escherichia coli aspartate transcarbamoylase based upon a structure of the enzyme complexed with the bisubstrate analogue N-phosphonacetyl-L-aspartate at 2.1 A.

Jin, L.Stec, B.Lipscomb, W.N.Kantrowitz, E.R.

(1999) Proteins 37: 729-742


  • PubMed Abstract: 
  • A high-resolution structure of Escherichia coli aspartate transcarbamoylase has been determined to 2.1 A; resolution in the presence of the bisubstrate analog N-phosphonacetyl-L-aspartate (PALA). The structure was refined to a free R-factor of 23.4% ...

    A high-resolution structure of Escherichia coli aspartate transcarbamoylase has been determined to 2.1 A; resolution in the presence of the bisubstrate analog N-phosphonacetyl-L-aspartate (PALA). The structure was refined to a free R-factor of 23.4% and a working R-factor of 20.3%. The PALA molecule is completely saturated with interactions to side chain and backbone groups in the active site, including two interactions that are contributed from the 80s loop of the adjacent catalytic chain. The charge neutralization of the bound PALA molecule (and presumably the substrates as well) induced by the electrostatic field of the highly positively charged active site is an important factor in the high binding affinity of PALA and must be important for catalysis. The higher-resolution structure reported here departs in a number of ways from the previously determined structure at lower resolution. These modifications include alterations in the backbone conformation of the C-terminal of the catalytic chains, the N- and C-termini of the regulatory chains, and two loops of the regulatory chain. The high-resolution of this structure has allowed a more detailed description of the binding of PALA to the active site of the enzyme and has allowed a detailed model of the tetrahedral intermediate to be constructed. This model becomes the basis of a description of the catalytic mechanism of the transcarbamoylase reaction. The R-structural state of the enzyme-PALA complex is an excellent representation of the form of the enzyme that occurs at the moment in the catalytic cycle when the tetrahedral intermediate is formed. Finally, improved electron density in the N-terminal region of the regulatory chain (residues 1 to 7) has allowed tracing of the entire regulatory chain. The N-terminal segments of the R1 and R6 chains are located in close proximity to each other and to the regulatory site. This portion of the molecule may be involved in the observed asymmetry between the regulatory binding sites as well as in the heterotropic response of the enzyme.


    Related Citations: 
    • Complex of N-phosphonacetyl-L-aspartate with Aspartate carbamoyltransferase
      Ke, H.,Lipscomb, W.N.,Cho, Y.,Honzatko, R.B.
      (1988) J.Mol.Biol. 204: 725


    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): 0 
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 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PAL
Query on PAL

Download SDF File 
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 SDF File 
Download CCD File 
B, D
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
PALKi: 27 nM BINDINGMOAD
PALKi: 27 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.203 
  • Space Group: P 3 2 1
Unit Cell:
Length (Å)Angle (°)
a = 122.240α = 90.00
b = 122.240β = 90.00
c = 156.360γ = 120.00
Software Package:
Software NamePurpose
X-PLORrefinement
SDMSdata reduction
X-PLORmodel building
SDMSdata scaling
X-PLORphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-01-28
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance