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The NO trafficking between dinitrosyl‐iron complexes (DNIC) and E. coli transcriptional factors containing iron‐sulfur clusters
Author(s) -
Yu Steve,
Lo Fengchun,
Hung MuCheng
Publication year - 2010
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.24.1_supplement.678.25
Subject(s) - iron–sulfur cluster , chemistry , superoxide dismutase , catalase , superoxide , oxidative stress , electron paramagnetic resonance , redox , biochemistry , gene , nitric oxide , sulfur , heme , inorganic chemistry , enzyme , organic chemistry , physics , nuclear magnetic resonance
SoxR protein is a transcriptional factor belonged to a member of the Mer family. The native form of the protein is presented as a dimeric structure and each monomer contains a redox‐active [2Fe‐2S] center. The iron‐sulfur cluster of SoxR is responsive to one‐electron oxidation by superoxide and resulted in subsequent expression of soxS gene for the rescue of oxidative stress such as the expression of superoxide dismutase or catalase. In addition to superoxide, SoxR is also sensitive to nitric oxide (NO) and its nitrosylated protein displayed paramagnetic features where its average g value is appeared at 2.03 in EPR. Despite the crystal structures of SoxR protein with and without the nucleic acids have already been unraveled [1], there is still not sufficient structural information to illustrate how the conformational changes mediated by redox chemistry or NO modulation [2] could lead with the transcriptional activation. In this study, we employed the x‐ray absorption spectroscopic methods to determine the structural insights of metal active sites in SoxR under the oxidized, reduced and nitrosylated conditions, respectively. We anticipate clarifying the major clues that control the corresponding gene regulations resulting from oxidative or nitrosative stress. Financial Support: National Science Council (NSC 98‐2627‐M‐001‐004‐) and Academia Sinica in Taipei