Forte 2019 Biochim Biophys Acta Bioenerg

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Forte E, Borisov VB, Siletsky SA, Petrosino M, Giuffre A (2019) In the respiratory chain of Escherichia coli cytochromes bd-I and bd-II are more sensitive to carbon monoxide inhibition than cytochrome bo3. Biochim Biophys Acta Bioenerg 1860:148088.

Β» PMID: 31669488

Forte E, Borisov VB, Siletsky SA, Petrosino M, Giuffre A (2019) Biochim Biophys Acta Bioenerg

Abstract: Bacteria can not only encounter carbon monoxide (CO) in their habitats but also produce the gas endogenously. Bacterial respiratory oxidases, thus, represent possible targets for CO. Accordingly, host macrophages were proposed to produce CO and release it into the surrounding microenvironment to sense viable bacteria through a mechanism that in Escherichia (E.) coli was suggested to involve the targeting of a bd-type respiratory oxidase by CO. The aerobic respiratory chain of E. coli possesses three terminal quinol:O2-oxidoreductases: the heme-copper oxidase bo3 and two copper-lacking bd-type oxidases, bd-I and bd-II. Heme-copper and bd-type oxidases differ in the mechanism and efficiency of proton motive force generation and in resistance to oxidative and nitrosative stress, cyanide and hydrogen sulfide. Here, we investigated at varied O2 concentrations the effect of CO gas on the O2 reductase activity of the purified cytochromes bo3, bd-I and bd-II of E. coli. We found that CO, in competition with O2, reversibly inhibits the three enzymes. The inhibition constants Ki for the bo3, bd-I and bd-II oxidases are 2.4β€―Β±β€―0.3, 0.04β€―Β±β€―0.01 and 0.2β€―Β±β€―0.1β€―ΞΌM CO, respectively. Thus, in E. coli, bd-type oxidases are more sensitive to CO inhibition than the heme-copper cytochrome bo3. The possible physiological consequences of this finding are discussed.

Copyright Β© 2019 Elsevier B.V. All rights reserved. β€’ Keywords: Carbon monoxide, Cytochrome bd, Escherichia coli, Inhibition, Respiratory chain, Terminal oxidases β€’ Bioblast editor: Plangger M β€’ O2k-Network Lab: IT Rome Sarti P

Labels: MiParea: Respiration 

Organism: Eubacteria 

Regulation: Oxygen kinetics 

HRR: Oxygraph-2k 

Labels, 2020-01 

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