pH-dependent kinetics of NO release from E. coli bd-I and bd-II oxidase reveals involvement of Asp/Glu58B.
Biochim Biophys Acta Bioenerg
; 1864(2): 148952, 2023 04 01.
Article
en En
| MEDLINE
| ID: mdl-36535430
Escherichia coli contains two cytochrome bd oxidases, bd-I and bd-II. The structure of both enzymes is highly similar, but they exhibit subtle differences such as the accessibility of the active site through a putative proton channel. Here, we demonstrate that the duroquinol:dioxygen oxidoreductase activity of bd-I increased with alkaline pH, whereas bd-II showed a broad activity maximum around pH 7. Likewise, the pH dependence of NO release from the reduced active site, an essential property of bd oxidases, differed between the two oxidases as detected by UV/vis spectroscopy. Both findings may be attributed to differences in the proton channel leading to the active site heme d. The channel comprises a titratable residue (Asp58B in bd-I and Glu58B in bd-II). Conservative mutations at this position drastically altered NO release demonstrating its contribution to the process.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oxidorreductasas
/
Proteínas de Escherichia coli
Idioma:
En
Revista:
Biochim Biophys Acta Bioenerg
Año:
2023
Tipo del documento:
Article
País de afiliación:
Francia
Pais de publicación:
Países Bajos