Mass spectrometric identification of intermediates in the O2-driven [4Fe-4S] to [2Fe-2S] cluster conversion in FNR

Crack, Jason C., Thomson, Andrew J. and Le Brun, Nick E. (2017) Mass spectrometric identification of intermediates in the O2-driven [4Fe-4S] to [2Fe-2S] cluster conversion in FNR. Proceedings of the National Academy of Sciences of the United States of America (PNAS), 114 (6). E3215–E3223.

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Abstract

The iron-sulfur cluster containing protein FNR is the master regulator for the switch between anaerobic and aerobic respiration in Escherichia coli and many other bacteria. The [4Fe-4S] cluster functions as the sensory module, undergoing reaction with O2 that leads to conversion to a [2Fe-2S] form with loss of high affinity DNA-binding. Here we report studies of the FNR cluster conversion reaction using time-resolved electrospray ionization mass spectrometry. The data provide new insight into the reaction, permitting the detection of cluster conversion intermediates and products, including a novel [3Fe-3S] cluster and persulfide coordinated [2Fe-2S] clusters ([2Fe-2S](S)n, where n = 1 or 2). Analysis of kinetic data revealed a branched mechanism in which cluster sulfide oxidation occurs in parallel with cluster conversion, and not as a subsequent, secondary reaction, to generate ([2Fe-2S](S)n species. This methodology shows great potential for broad application to studies of protein cofactorsmall molecule interactions.

Item Type: Article
Additional Information: Early title: O2-sensing by [4Fe-4S] FNR: identification of intermediates during cluster conversion by mass spectrometry
Faculty \ School: Faculty of Science > School of Chemistry
Depositing User: Pure Connector
Date Deposited: 15 Mar 2017 01:41
Last Modified: 22 Apr 2020 02:57
URI: https://ueaeprints.uea.ac.uk/id/eprint/62965
DOI: 10.1073/pnas.1620987114

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