Direct Electron Transfer between the frhAGB-Encoded Hydrogenase and Thioredoxin Reductase in the Nonmethanogenic Archaeon Thermococcus onnurineus NA1.
Appl Environ Microbiol
; 86(6)2020 03 02.
Article
em En
| MEDLINE
| ID: mdl-31924613
ABSTRACT
To date, NAD(P)H, ferredoxin, and coenzyme F420 have been identified as electron donors for thioredoxin reductase (TrxR). In this study, we present a novel electron source for TrxR. In the hyperthermophilic archaeon Thermococcus onnurineus NA1, the frhAGB-encoded hydrogenase, a homolog of the F420-reducing hydrogenase of methanogens, was demonstrated to interact with TrxR in coimmunoprecipitation experiments and in vitro pulldown assays. Electrons derived from H2 oxidation by the frhAGB-encoded hydrogenase were transferred to TrxR and reduced Pdo, a redox partner of TrxR. Interaction and electron transfer were observed between TrxR and the heterodimeric hydrogenase complex (FrhAG) as well as the heterotrimeric complex (FrhAGB). Hydrogen-dependent reduction of TrxR was 7-fold less efficient than when NADPH was the electron donor. This study not only presents a different type of electron donor for TrxR but also reveals new functionality of the frhAGB-encoded hydrogenase utilizing a protein as an electron acceptor.IMPORTANCE This study has importance in that TrxR can use H2 as an electron donor with the aid of the frhAGB-encoded hydrogenase as well as NAD(P)H in T. onnurineus NA1. Further studies are needed to explore the physiological significance of this protein. This study also has importance as a significant step toward understanding the functionality of the frhAGB-encoded hydrogenase in a nonmethanogen; the hydrogenase can transfer electrons derived from oxidation of H2 to a protein target by direct contact without the involvement of an electron carrier, which is distinct from the mechanism of its homologs, F420-reducing hydrogenases of methanogens.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tiorredoxina Dissulfeto Redutase
/
Thermococcus
/
Proteínas Arqueais
/
Elétrons
/
Hidrogenase
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article