Nitric Oxide Does Not Inhibit but Is Metabolized by the Cytochrome bcc-aa3 Supercomplex

Autor: Elena Forte, Li-Shar Huang, Edward A. Berry, Vitaliy B. Borisov, Alessandro Giuffrè
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: International Journal of Molecular Sciences
Volume 21
Issue 22
International journal of molecular sciences
21 (2020): 1–12. doi:10.3390/ijms21228521
info:cnr-pdr/source/autori:Forte, Elena; Giuffrè, Alessandro; Huang, Li Shar; Berry, Edward A.; Borisov, Vitaliy B./titolo:Nitric oxide does not inhibit but is metabolized by the cytochrome bcc-aa3<%2Finf> supercomplex/doi:10.3390%2Fijms21228521/rivista:International journal of molecular sciences (Print)/anno:2020/pagina_da:1/pagina_a:12/intervallo_pagine:1–12/volume:21
ISSN: 1422-0067
DOI: 10.3390/ijms21228521
Popis: Nitric oxide (NO) is a well-known active site ligand and inhibitor of respiratory terminal oxidases. Here, we investigated the interaction of NO with a purified chimeric bcc-aa3 supercomplex composed of Mycobacterium tuberculosis cytochrome bcc and Mycobacterium smegmatisaa3-type terminal oxidase. Strikingly, we found that the enzyme in turnover with O2 and reductants is resistant to inhibition by the ligand, being able to metabolize NO at 25 °
C with an apparent turnover number as high as &asymp
303 mol NO (mol enzyme)&minus
1 min&minus
1 at 30 µ
M NO. The rate of NO consumption proved to be proportional to that of O2 consumption, with 2.65 ±
0.19 molecules of NO being consumed per O2 molecule by the mycobacterial bcc-aa3. The enzyme was found to metabolize the ligand even under anaerobic reducing conditions with a turnover number of 2.8 ±
0.5 mol NO (mol enzyme)&minus
1 at 25 °
C and 8.4 µ
M NO. These results suggest a protective role of mycobacterial bcc-aa3 supercomplexes against NO stress.
Databáze: OpenAIRE
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