Experimental Data Snapshot

  • Resolution: 2.90 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.201 

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This is version 1.4 of the entry. See complete history


The crystal structure of cystathionine gamma-synthase from Nicotiana tabacum reveals its substrate and reaction specificity.

Steegborn, C.Messerschmidt, A.Laber, B.Streber, W.Huber, R.Clausen, T.

(1999) J Mol Biol 290: 983-996

  • DOI: https://doi.org/10.1006/jmbi.1999.2935
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Cystathionine gamma-synthase catalyses the committed step of de novo methionine biosynthesis in micro-organisms and plants, making the enzyme an attractive target for the design of new antibiotics and herbicides. The crystal structure of cystathionine gamma-synthase from Nicotiana tabacum has been solved by Patterson search techniques using the structure of Escherichia coli cystathionine gamma-synthase. The model was refined at 2.9 A resolution to a crystallographic R -factor of 20.1 % (Rfree25.0 %). The physiological substrates of the enzyme, L-homoserine phosphate and L-cysteine, were modelled into the unliganded structure. These complexes support the proposed ping-pong mechanism for catalysis and illustrate the dissimilar substrate specificities of bacterial and plant cystathionine gamma-synthases on a molecular level. The main difference arises from the binding modes of the distal substrate groups (O -acetyl/succinyl versusO -phosphate). Central in fixing the distal phosphate of the plant CGS substrate is an exposed lysine residue that is strictly conserved in plant cystathionine gamma-synthases whereas bacterial enzymes carry a glycine residue at this position. General insight regarding the reaction specificity of transsulphuration enzymes is gained by the comparison to cystathionine beta-lyase from E. coli, indicating the mechanistic importance of a second substrate binding site for L-cysteine which leads to different chemical reaction types.

  • Organizational Affiliation

    Abteilung Strukturforschung, Am Klopferspitz 18a, Planegg-Martinsried, D-82152, Germany. steegbo@biochem.mpg.de

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D, E
A, B, C, D, E, F, G, H
445Nicotiana tabacumMutation(s): 0 
Gene Names: METB
Find proteins for Q9ZPL5 (Nicotiana tabacum)
Explore Q9ZPL5 
Go to UniProtKB:  Q9ZPL5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9ZPL5
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.90 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.201 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 120α = 90
b = 129.5β = 90
c = 309.8γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
CCP4data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-08-25
    Type: Initial release
  • Version 1.1: 2008-04-26
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 1.3: 2018-06-13
    Changes: Data collection
  • Version 1.4: 2023-08-16
    Changes: Data collection, Database references, Derived calculations, Refinement description