Structure of Arabidopsis chloroplastic monothiol glutaredoxin AtGRXcp

Acta Crystallogr D Biol Crystallogr. 2010 Jun;66(Pt 6):725-32. doi: 10.1107/S0907444910013119. Epub 2010 May 15.

Abstract

Monothiol glutaredoxins (Grxs) play important roles in maintaining redox homeostasis in living cells and are conserved across species. Arabidopsis thaliana monothiol glutaredoxin AtGRXcp is critical for protection from oxidative stress in chloroplasts. The crystal structure of AtGRXcp has been determined at 2.4 A resolution. AtGRXcp has a glutaredoxin/thioredoxin-like fold with distinct structural features that differ from those of dithiol Grxs. The structure reveals that the putative active-site motif CGFS is well defined and is located on the molecular surface and that a long groove extends to both sides of the catalytic Cys97. Structural comparison and molecular modeling suggest that glutathione can bind in this groove and form extensive interactions with conserved charged residues including Lys89, Arg126 and Asp152. Further comparative studies reveal that a unique loop with five additional residues adjacent to the active-site motif may be a key structural feature of monothiol Grxs and may influence their function. This study provides the first structural information on plant CGFS-type monothiol Grxs, allowing a better understanding of the redox-regulation mechanism mediated by these plant Grxs.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Antiporters
  • Arabidopsis / chemistry*
  • Arabidopsis Proteins / chemistry*
  • Arabidopsis Proteins / genetics
  • Carrier Proteins / chemistry*
  • Carrier Proteins / genetics
  • Chloroplasts / chemistry*
  • Crystallography, X-Ray
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Sequence Alignment
  • Structural Homology, Protein
  • Sulfhydryl Compounds / chemistry*

Substances

  • Antiporters
  • Arabidopsis Proteins
  • CXIP1 protein, Arabidopsis
  • Carrier Proteins
  • Sulfhydryl Compounds