1C3O

CRYSTAL STRUCTURE OF THE CARBAMOYL PHOSPHATE SYNTHETASE: SMALL SUBUNIT MUTANT C269S WITH BOUND GLUTAMINE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.188 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The small subunit of carbamoyl phosphate synthetase: snapshots along the reaction pathway.

Thoden, J.B.Huang, X.Raushel, F.M.Holden, H.M.

(1999) Biochemistry 38: 16158-16166

  • Primary Citation of Related Structures:  1C30, 1CS0

  • PubMed Abstract: 
  • Carbamoyl phosphate synthetase (CPS) plays a key role in both arginine and pyrimidine biosynthesis by catalyzing the production of carbamoyl phosphate. The enzyme from Escherichi coli consists of two polypeptide chains referred to as the small and la ...

    Carbamoyl phosphate synthetase (CPS) plays a key role in both arginine and pyrimidine biosynthesis by catalyzing the production of carbamoyl phosphate. The enzyme from Escherichi coli consists of two polypeptide chains referred to as the small and large subunits. On the basis of both amino acid sequence analyses and X-ray structural studies, it is known that the small subunit belongs to the Triad or Type I class of amidotransferases, all of which contain a cysteine-histidine (Cys269 and His353) couple required for activity. The hydrolysis of glutamine by the small subunit has been proposed to occur via two tetrahedral intermediates and a glutamyl-thioester moiety. Here, we describe the three-dimensional structures of the C269S/glutamine and CPS/glutamate gamma-semialdehyde complexes, which serve as mimics for the Michaelis complex and the tetrahedral intermediates, respectively. In conjunction with the previously solved glutamyl-thioester intermediate complex, the stereochemical course of glutamine hydrolysis in CPS has been outlined. Specifically, attack by the thiolate of Cys269 occurs at the Si face of the carboxamide group of the glutamine substrate leading to a tetrahedral intermediate with an S-configuration. Both the backbone amide groups of Gly241 and Leu270, and O(gamma) of Ser47 play key roles in stabilizing the developing oxyanion. Collapse of the tetrahedral intermediate leads to formation of the glutamyl-thioester intermediate, which is subsequently attacked at the Si face by an activated water molecule positioned near His353. The results described here serve as a paradigm for other members of the Triad class of amidotranferases.


    Organizational Affiliation

    Department of Biochemistry, University of Wisconsin-Madison 53705, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CARBAMOYL PHOSPHATE SYNTHETASE: LARGE SUBUNIT
A, C, E, G
1073Escherichia coli (strain K12)Gene Names: carB (pyrA)
EC: 6.3.5.5
Find proteins for P00968 (Escherichia coli (strain K12))
Go to UniProtKB:  P00968
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
CARBAMOYL PHOSPHATE SYNTHETASE: SMALL SUBUNIT
B, D, F, H
382Escherichia coli (strain K12)Gene Names: carA (pyrA)
EC: 6.3.5.5
Find proteins for P0A6F1 (Escherichia coli (strain K12))
Go to UniProtKB:  P0A6F1
Small Molecules
Ligands 8 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
K
Query on K

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Download CCD File 
A, B, C, D, E, F, G, H
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
MN
Query on MN

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Download CCD File 
A, C, E, G
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
PO4
Query on PO4

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Download CCD File 
A, C, E, G
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
ADP
Query on ADP

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Download CCD File 
A, C, E, G
ADENOSINE-5'-DIPHOSPHATE
C10 H15 N5 O10 P2
XTWYTFMLZFPYCI-KQYNXXCUSA-N
 Ligand Interaction
CL
Query on CL

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Download CCD File 
A, B, C, D, E, F, G, H
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
GLN
Query on GLN

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Download CCD File 
A, B, C, D, E, F, G, H
GLUTAMINE
C5 H10 N2 O3
ZDXPYRJPNDTMRX-VKHMYHEASA-N
 Ligand Interaction
NET
Query on NET

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Download CCD File 
A, C, E, G
TETRAETHYLAMMONIUM ION
C8 H20 N
CBXCPBUEXACCNR-UHFFFAOYSA-N
 Ligand Interaction
ORN
Query on ORN

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Download CCD File 
A, C, E, G
L-ornithine
C5 H12 N2 O2
AHLPHDHHMVZTML-BYPYZUCNSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.188 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 152.500α = 90.00
b = 164.400β = 90.00
c = 332.600γ = 90.00
Software Package:
Software NamePurpose
AMoREphasing
d*TREKdata reduction
TNTrefinement
HKL-2000data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-12-10
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Non-polymer description, Version format compliance