1Z7W

Crystal Structure of O-Acetylserine Sulfhydrylase from Arabidopsis thaliana


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.186 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Molecular Basis of Cysteine Biosynthesis in Plants: STRUCTURAL AND FUNCTIONAL ANALYSIS OF O-ACETYLSERINE SULFHYDRYLASE FROM ARABIDOPSIS THALIANA.

Bonner, E.R.Cahoon, R.E.Knapke, S.M.Jez, J.M.

(2005) J Biol Chem 280: 38803-38813

  • DOI: 10.1074/jbc.M505313200
  • Primary Citation of Related Structures:  
    1Z7Y, 1Z7W

  • PubMed Abstract: 
  • In plants, cysteine biosynthesis plays a central role in fixing inorganic sulfur from the environment and provides the only metabolic sulfide donor for the generation of methionine, glutathione, phytochelatins, iron-sulfur clusters, vitamin cofactors ...

    In plants, cysteine biosynthesis plays a central role in fixing inorganic sulfur from the environment and provides the only metabolic sulfide donor for the generation of methionine, glutathione, phytochelatins, iron-sulfur clusters, vitamin cofactors, and multiple secondary metabolites. O-Acetylserine sulfhydrylase (OASS) catalyzes the final step of cysteine biosynthesis, the pyridoxal 5'-phosphate (PLP)-dependent conversion of O-acetylserine into cysteine. Here we describe the 2.2 A resolution crystal structure of OASS from Arabidopsis thaliana (AtOASS) and the 2.7 A resolution structure of the AtOASS K46A mutant with PLP and methionine covalently linked as an external aldimine in the active site. Although the plant and bacterial OASS share a conserved set of amino acids for PLP binding, the structure of AtOASS reveals a difference from the bacterial enzyme in the positioning of an active site loop formed by residues 74-78 when methionine is bound. Site-directed mutagenesis, kinetic analysis, and ligand binding titrations probed the functional roles of active site residues. These experiments indicate that Asn(77) and Gln(147) are key amino acids for O-acetylserine binding and that Thr(74) and Ser(75) are involved in sulfur incorporation into cysteine. In addition, examination of the AtOASS structure and nearly 300 plant and bacterial OASS sequences suggest that the highly conserved beta8A-beta9A surface loop may be important for interaction with serine acetyltransferase, the other enzyme in cysteine biosynthesis. Initial protein-protein interaction experiments using AtOASS mutants targeted to this loop support this hypothesis.


    Organizational Affiliation

    Donald Danforth Plant Science Center, St. Louis, Missouri 63132, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Cysteine synthaseA322Arabidopsis thalianaMutation(s): 0 
Gene Names: OASA1OAS1OASSOLD3At4g14880dl3480c
EC: 2.5.1.47
Find proteins for P47998 (Arabidopsis thaliana)
Explore P47998 
Go to UniProtKB:  P47998
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PLP
Query on PLP

Download CCD File 
A
PYRIDOXAL-5'-PHOSPHATE
C8 H10 N O6 P
NGVDGCNFYWLIFO-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.186 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 105.153α = 90
b = 105.153β = 90
c = 100.133γ = 90
Software Package:
Software NamePurpose
PROTEUM PLUSdata collection
PROTEUM PLUSdata reduction
CNSrefinement
PROTEUM PLUSdata scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-09-20
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance