Characterization of the RnfB and RnfG subunits of the Rnf complex from the archaeon Methanosarcina acetivorans.

ABSTRACT: Rnf complexes are redox-driven ion pumps identified in diverse species from the domains Bacteria and Archaea, biochemical characterizations of which are reported for two species from the domain Bacteria. Here, we present characterizations of the redox-active subunits RnfG and RnfB from the Rnf complex of Methanosarcina acetivorans, an acetate-utilizing methane-producing species from the domain Archaea. The purified RnfG subunit produced in Escherichia coli fluoresced in SDS-PAGE gels under UV illumination and showed a UV-visible spectrum typical of flavoproteins. The Thr166Gly variant of RnfG was colorless and failed to fluoresce under UV illumination confirming a role for Thr166 in binding FMN. Redox titration of holo-RnfG revealed a midpoint potential of -129 mV for FMN with n = 2. The o

SUBMITTER: Suharti S 

PROVIDER: S-EPMC4023990 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature