| Autor: |
Jason C. Crack, Patricia Amara, Eve de Rosny, Claudine Darnault, Melanie R. Stapleton, Jeffrey Green, Anne Volbeda, Juan C. Fontecilla-Camps, Nick E. Le Brun |
| Jazyk: |
angličtina |
| Rok vydání: |
2023 |
| Předmět: |
|
| Zdroj: |
Inorganics, Vol 11, Iss 12, p 450 (2023) |
| Druh dokumentu: |
article |
| ISSN: |
2304-6740 |
| DOI: |
10.3390/inorganics11120450 |
| Popis: |
The Escherichia coli fumarate and nitrate reduction (FNR) regulator acts as the cell’s master switch for the transition between anaerobic and aerobic respiration, controlling the expression of >300 genes in response to O2 availability. Oxygen is perceived through a reaction with FNR’s [4Fe-4S] cluster cofactor. In addition to its primary O2 signal, the FNR [4Fe-4S] cluster also reacts with nitric oxide (NO). In response to physiological concentrations of NO, FNR de-represses the transcription of hmp, which encodes a principal NO-detoxifying enzyme, and fails to activate the expression of the nitrate reductase (nar) operon, a significant source of endogenous cellular NO. Here, we show that the L28H variant of FNR, which is much less reactive towards O2 than wild-type FNR, remains highly reactive towards NO. A high resolution structure and molecular dynamics (MD) simulations of the closely related L28H-FNR from Aliivibrio fischeri revealed decreased conformational flexibility of the Cys20-Cys29 cluster-binding loop that is suggested to inhibit outer-sphere O2 reactivity, but only partially impair inner-sphere NO reactivity. Our data provide new insights into the mechanistic basis for how iron–sulfur cluster regulators can distinguish between O2 and NO. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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