1N31

Structure of A Catalytically Inactive Mutant (K223A) of C-DES with a Substrate (Cystine) Linked to the Co-Factor


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.196 

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This is version 1.2 of the entry. See complete history


Literature

Snapshots of the Cystine Lyase "C-DES" during Catalysis: Studies in Solution and in the Crystalline State

Kaiser, J.T.Bruno, S.Clausen, T.Huber, R.Schiaretti, F.Mozzarelli, A.Kessler, D.

(2003) J Biol Chem 278: 357-365

  • DOI: 10.1074/jbc.M209862200
  • Primary Citation of Related Structures:  
    1N2T, 1N31

  • PubMed Abstract: 
  • The cystine lyase (C-DES) of Synechocystis is a pyridoxal-5'-phosphate-dependent enzyme distantly related to the family of NifS-like proteins. The crystal structure of an N-terminal modified variant has recently been determined. Herein, the reactivit ...

    The cystine lyase (C-DES) of Synechocystis is a pyridoxal-5'-phosphate-dependent enzyme distantly related to the family of NifS-like proteins. The crystal structure of an N-terminal modified variant has recently been determined. Herein, the reactivity of this enzyme variant was investigated spectroscopically in solution and in the crystalline state to follow the course of the reaction and to determine the catalytic mechanism on a molecular level. Using the stopped-flow technique, the reaction with the preferred substrate cystine was found to follow biphasic kinetics leading to the formation of absorbing species at 338 and 470 nm, attributed to the external aldimine and the alpha-aminoacrylate; the reaction with cysteine also exhibited biphasic behavior but only the external aldimine accumulated. The same reaction intermediates were formed in crystals as seen by polarized absorption microspectrophotometry, thus indicating that C-DES is catalytically competent in the crystalline state. The three-dimensional structure of the catalytically inactive mutant C-DES(K223A) in the presence of cystine showed the formation of an external aldimine species, in which two alternate conformations of the substrate were observed. The combined results allow a catalytic mechanism to be proposed involving interactions between cystine and the active site residues Arg-360, Arg-369, and Trp-251*; these residues reorient during the beta-elimination reaction, leading to the formation of a hydrophobic pocket that stabilizes the enolimine tautomer of the aminoacrylate and the cysteine persulfide product.


    Organizational Affiliation

    Max-Planck-Institut für Biochemie, Abt. Strukturforschung, Am Klopferspitz 18a, Martinsried 82152, Germany. kaiser@biochem.mpg.de



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
L-cysteine/cystine lyase C-DESAB386Synechocystis sp. PCC 6714Mutation(s): 1 
Gene Names: c-des
EC: 4.4.1
Find proteins for Q9ZHG9 (Synechocystis sp. (strain PCC 6714))
Explore Q9ZHG9 
Go to UniProtKB:  Q9ZHG9
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PLP
Query on PLP

Download CCD File 
A, B
PYRIDOXAL-5'-PHOSPHATE
C8 H10 N O6 P
NGVDGCNFYWLIFO-UHFFFAOYSA-N
 Ligand Interaction
CYS
Query on CYS

Download CCD File 
A, B
CYSTEINE
C3 H7 N O2 S
XUJNEKJLAYXESH-REOHCLBHSA-N
 Ligand Interaction
K
Query on K

Download CCD File 
A, B
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.196 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 62.681α = 90
b = 65.843β = 90
c = 172.563γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
MOLREPphasing
CNSrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-01-21
    Type: Initial release
  • Version 1.1: 2008-04-28
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance