O2-Tolerant H2 Activation by an Isolated Large Subunit of a [NiFe] Hydrogenase.
Biochemistry
; 57(36): 5339-5349, 2018 09 11.
Article
en En
| MEDLINE
| ID: mdl-30110155
ABSTRACT
The catalytic properties of hydrogenases are nature's answer to the seemingly simple reaction H2 â 2H+ + 2e-. Members of the phylogenetically diverse subgroup of [NiFe] hydrogenases generally consist of at least two subunits, where the large subunit harbors the H2-activating [NiFe] site and the small subunit contains iron-sulfur clusters mediating e- transfer. Typically, [NiFe] hydrogenases are susceptible to inhibition by O2. Here, we conducted system minimization by isolating and analyzing the large subunit of one of the rare members of the group of O2-tolerant [NiFe] hydrogenases, namely the preHoxG protein of the membrane-bound hydrogenase from Ralstonia eutropha. Unlike previous assumptions, preHoxG was able to activate H2 as it clearly performed catalytic hydrogen/deuterium exchange. However, it did not execute the entire catalytic cycle described for [NiFe] hydrogenases. Remarkably, H2 activation was performed by preHoxG even in the presence of O2, although the unique [4Fe-3S] cluster located in the small subunit and described to be crucial for tolerance toward O2 was absent. These findings challenge the current understanding of O2 tolerance of [NiFe] hydrogenases. The applicability of this minimal hydrogenase in basic and applied research is discussed.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Oxígeno
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Proteínas Bacterianas
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Cupriavidus necator
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Hidrógeno
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Hidrogenasas
Idioma:
En
Revista:
Biochemistry
Año:
2018
Tipo del documento:
Article
País de afiliación:
Alemania