Reactions of nitric oxide and oxygen with the regulator of fumarate and nitrate reduction, a global transcriptional regulator, during anaerobic growth of Escherichia coli.
Crack, Jason C;
Le Brun, Nick E;
Thomson, Andrew J;
Green, Jeffrey;
Jervis, Adrian J;
(2008)
Reactions of nitric oxide and oxygen with the regulator of fumarate and nitrate reduction, a global transcriptional regulator, during anaerobic growth of Escherichia coli.
Methods in enzymology, 437.
pp. 191-209.
ISSN 0076-6879
DOI: https://doi.org/10.1016/S0076-6879(07)37011-0
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The Escherichia coli fumarate and nitrate reductase (FNR) regulator protein is an important transcriptional regulator that controls the expression of a large regulon of more than 100 genes in response to changes in oxygen availability. FNR is active when it acquires a [4Fe-4S](2+) cluster under anaerobic conditions. The presence of the [4Fe-4S](2+) cluster promotes protein dimerization and site-specific DNA binding, facilitating activation or repression of target promoters. Oxygen is sensed by the controlled disassembly of the [4Fe-4S](2+) cluster, ultimately resulting in inactive, monomeric, apo-FNR. The FNR [4Fe-4S](2+) cluster is also sensitive to nitric oxide, such that under anaerobic conditions the protein is inactivated by nitrosylation of the iron-sulfur cluster, yielding a mixture of monomeric and dimeric dinitrosyl-iron cysteine species. This chapter describes some of the methods used to produce active [4Fe-4S] FNR protein and investigates the reaction of the [4Fe-4S](2+) cluster with nitric oxide and oxygen in vitro.