1Z7W

Crystal Structure of O-Acetylserine Sulfhydrylase from Arabidopsis thaliana


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 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:  

  • 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: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cysteine synthase
A
322Arabidopsis thalianaMutation(s): 0 
Gene Names: OASA1 (OAS1, OASS, OLD3)
EC: 2.5.1.47
Find proteins for P47998 (Arabidopsis thaliana)
Go to UniProtKB:  P47998
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
PLP
Query on PLP

Download SDF File 
Download CCD File 
A
PYRIDOXAL-5'-PHOSPHATE
VITAMIN B6 Phosphate
C8 H10 N O6 P
NGVDGCNFYWLIFO-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 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 = 90.00
b = 105.153β = 90.00
c = 100.133γ = 90.00
Software Package:
Software NamePurpose
PROTEUM PLUSdata reduction
CNSphasing
PROTEUM PLUSdata collection
CNSrefinement
PROTEUM PLUSdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

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