Structural insights into the mechanism of oxidative activation of heme-free H-NOX from Vibrio cholerae.
Biochem J
; 477(6): 1123-1136, 2020 03 27.
Article
en En
| MEDLINE
| ID: mdl-32141496
ABSTRACT
Bacterial heme nitric oxide/oxygen (H-NOX) domains are nitric oxide (NO) or oxygen sensors. This activity is mediated through binding of the ligand to a heme cofactor. However, H-NOX from Vibrio cholerae (Vc H-NOX) can be easily purified in a heme-free state that is capable of reversibly responding to oxidation, suggesting a heme-independent function as a redox sensor. This occurs by oxidation of Cys residues at a zinc-binding site conserved in a subset of H-NOX homologs. Remarkably, zinc is not lost from the protein upon oxidation, although its ligation environment is significantly altered. Using a combination of computational and experimental approaches, we have characterized localized structural changes that accompany the formation of specific disulfide bonds between Cys residues upon oxidation. Furthermore, the larger-scale structural changes accompanying oxidation appear to mimic those changes observed upon NO binding to the heme-bound form. Thus, Vc H-NOX and its homologs may act as both redox and NO sensors by completely separate mechanisms.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas Bacterianas
/
Vibrio cholerae
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Estrés Oxidativo
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Hemo
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Óxido Nítrico
Idioma:
En
Revista:
Biochem J
Año:
2020
Tipo del documento:
Article
País de afiliación:
Estados Unidos