Crystal Structure of the Arabidopsis thaliana O-Acetyl-Serine-(Thiol)- Lyase C

Experimental Data Snapshot

  • Resolution: 2.40 Å
  • R-Value Free: 0.233 
  • R-Value Work: 0.180 
  • R-Value Observed: 0.183 

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Allosterically Gated Enzyme Dynamics in the Cysteine Synthase Complex Regulate Cysteine Biosynthesis in Arabidopsis Thaliana.

Feldman-Salit, A.Wirtz, M.Lenherr, E.D.Throm, C.Hothorn, M.Scheffzek, K.Hell, R.Wade, R.C.

(2012) Structure 20: 292

  • DOI: https://doi.org/10.1016/j.str.2011.11.019
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Plants and bacteria assimilate sulfur into cysteine. Cysteine biosynthesis involves a bienzyme complex, the cysteine synthase complex (CSC), which consists of serine-acetyl-transferase (SAT) and O-acetyl-serine-(thiol)-lyase (OAS-TL) enzymes. The activity of OAS-TL is reduced by formation of the CSC. Although this reduction is an inherent part of the self-regulation cycle of cysteine biosynthesis, there has until now been no explanation as to how OAS-TL loses activity in plants. Complexation of SAT and OAS-TL involves binding of the C-terminal tail of SAT in one of the active sites of the homodimeric OAS-TL. We here explore the flexibility of the unoccupied active site in Arabidopsis thaliana cytosolic and mitochondrial OAS-TLs. Our results reveal two gates in the OAS-TL active site that define its accessibility. The observed dynamics of the gates show allosteric closure of the unoccupied active site of OAS-TL in the CSC, which can hinder substrate binding, abolishing its turnover to cysteine.

  • Organizational Affiliation

    Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), 69118 Heidelberg, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
430Arabidopsis thalianaMutation(s): 0 
Find proteins for Q43725 (Arabidopsis thaliana)
Explore Q43725 
Go to UniProtKB:  Q43725
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ43725
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.40 Å
  • R-Value Free: 0.233 
  • R-Value Work: 0.180 
  • R-Value Observed: 0.183 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 65.39α = 90
b = 65.39β = 90
c = 293.05γ = 90
Software Package:
Software NamePurpose

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-02-22
    Type: Initial release
  • Version 1.1: 2019-05-08
    Changes: Data collection, Derived calculations, Experimental preparation, Other
  • Version 1.2: 2023-12-20
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description