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The N‐terminal GIY‐YIG endonuclease activity of Arabidopsis glutaredoxin AtGRXS16
Author(s) -
Cheng Ninghui,
Liu Xi,
Liu Shian,
Feng Yingang,
Deng Haiteng,
Hirschi Kendal D.,
Wang Xinquan
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.558.5
Subject(s) - nuclease , endonuclease , glutaredoxin , biogenesis , dna , chloroplast , arabidopsis , biochemistry , biology , microbiology and biotechnology , chemistry , thioredoxin , enzyme , gene , mutant
A chloroplastic monothiol glutaredoxin, AtGRXS16, comprises two distinct functional domains, an N‐terminal GIY‐YIG endonuclease motif (NTD) and a C‐terminal Grx module, to coordinate redox regulation and DNA cleavage in chloroplasts. Structural determination of AtGRXS16‐NTD showed that it possesses a GIY‐YIG endonuclease fold, but the critical residues for the nuclease activity are different from typical GIY‐YIG endonucleases. AtGRXS16‐NTD was able to cleave λDNA and chloroplast genomic DNA and the nuclease activity was significantly reduced in AtGRXS16. AtGRXS16‐NTD could inhibit the ability of AtGRXS16 to suppress the sensitivity of yeast grx5 cells to oxidative stress; however, AtGRXS16 with a Cys123Ser mutation were active in these cells and functional in Fe‐S cluster biogenesis. Furthermore, the two functional domains were shown to be negatively regulated through a formation of an intramolecular disulfide bond. These findings unravel a novel manner of regulation for Grxs and provide insights into the mechanistic link between redox regulation and DNA metabolism in chloroplasts. This study is supported by USDA Cris fund.