Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1996 Sep 17;93(19):10094-8.
doi: 10.1073/pnas.93.19.10094.

SoxR, a [2Fe-2S] transcription factor, is active only in its oxidized form

P Gaudu  1 , B Weiss
Affiliations

SoxR, a [2Fe-2S] transcription factor, is active only in its oxidized form

P Gaudu et al. Proc Natl Acad Sci U S A. .

Abstract

SoxR protein is known to function both as a sensor and as a transcriptional activator for a superoxide response regulon in Escherichia coli. The activity of SoxR was tested by its ability to enable the transcription of its target gene, soxS, in vitro. The activity of the oxidized form was lost when its [2Fe-2S] clusters were reduced by dithionite under anaerobic conditions, and it was rapidly restored by autooxidation. This result is consistent with the hypothesis that induction of the regulon is effected by the univalent oxidation of the Fe-S centers of SoxR. In vivo, this oxidation may be caused by an alteration of the redox balance of electron chain intermediates that normally maintains soxR in an inactive, reduced state. Oxidized SoxR was about twice as effective as reduced SoxR in protecting the soxS operator from endonucleolytic cleavage. However, this difference could not account for a greater than 50-fold difference in their activities and therefore could not support a model in which oxidation activates SoxR by enabling it to bind to DNA. NADPH, ferredoxin, flavodoxin, or ferredoxin (flavodoxin):NADP+ reductase could not reduce SoxR directly in vitro at a measurable rate. The midpoint potential for SoxR was measured at -283 mV.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Hoppe Seylers Z Physiol Chem. 1971 Mar;352(3):433-46 - PubMed
    1. EMBO J. 1994 Jan 1;13(1):138-46 - PubMed
    1. Arch Biochem Biophys. 1979 Sep;196(2):385-95 - PubMed
    1. J Biol Chem. 1981 Dec 25;256(24):12673-80 - PubMed
    1. Eur J Biochem. 1982 Apr;123(3):563-9 - PubMed

Publication types

MeSH terms

LinkOut - more resources