Mechanistic Insight into the Nitrosylation of the [4Fe−4S] Cluster of WhiB-like Proteins

Crack, Jason C., Smith, Laura J., Stapleton, Melanie R., Peck, Jamie, Watmough, Nicholas J., Buttner, Mark J., Buxton, Roger S., Green, Jeffrey, Oganesyan, Vasily S., Thomson, Andrew J. and Le Brun, Nick E. (2011) Mechanistic Insight into the Nitrosylation of the [4Fe−4S] Cluster of WhiB-like Proteins. Journal of the American Chemical Society, 133 (4). pp. 1112-1121. ISSN 0002-7863

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Abstract

The reactivity of protein bound iron-sulfur clusters with nitric oxide (NO) is well documented, but little is known about the actual mechanism of cluster nitrosylation. Here, we report studies of members of the Wbl family of [4Fe-4S] containing proteins, which play key roles in regulating developmental processes in actinomycetes, including Streptomyces and Mycobacteria, and have been shown to be NO responsive. Streptomyces coelicolor WhiD and Mycobacterium tuberculosis WhiB1 react extremely rapidly with NO in a multiphasic reaction involving, remarkably, 8 NO molecules per [4Fe-4S] cluster. The reaction is 104-fold faster than that observed with O2 and is by far the most rapid iron-sulfur cluster nitrosylation reaction reported to date. An overall stoichiometry of [Fe4S4(Cys)4]2- + 8NO ? 2[FeI2(NO)4(Cys)2]0 + S2- + 3S0 has been established by determination of the sulfur products and their oxidation states. Kinetic analysis leads to a four-step mechanism that accounts for the observed NO dependence. DFT calculations suggest the possibility that the nitrosylation product is a novel cluster [FeI4(NO)8(Cys)4]0 derived by dimerization of a pair of Roussin’s red ester (RRE) complexes.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
Faculty of Science > School of Biological Sciences
Depositing User: Users 2731 not found.
Date Deposited: 14 Feb 2011 13:39
Last Modified: 21 Apr 2020 16:43
URI: https://ueaeprints.uea.ac.uk/id/eprint/21341
DOI: 10.1021/ja109581t

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