tailieunhanh - Báo cáo khoa học: The tungsten-containing formate dehydrogenase from Methylobacterium extorquens AM1: Purification and properties

NAD-dependent formate dehydrogenase (FDH1) was isolated from the a-proteobacterium Methylobacterium extorquensAM1 under oxic conditions. The enzyme was found to be a heterodimer of two subunits (a1b1)of107 and 61 kDa, respectively. The purified enzyme contained per mol enzyme 5 mol nonheme iron and acid-labile sulfur, mol noncovalently bound FMN, and mol tungsten. | Eur. J. Biochem. 270 325-333 2003 FEBS 2003 doi The tungsten-containing formate dehydrogenase from Methylobacterium extorquens AM1 Purification and properties Markus Laukel1 2 Ludmila Chistoserdova3 Mary E. Lidstrom3 4 and Julia A. Vorholt2 1 Max-Planck-Institut fur terrestrische Mikrobiologie Marburg Germany 2Laboratoire de Biologie Moléculaire des Relations Plantes-Microorganismes INRA CNRS Castanet-Tolosan France 3Department of Chemical Engineering and 4Department of Microbiology University of Washington Seattle Washington USA NAD-dependent formate dehydrogenase FDH1 was isolated from the a-proteobacterium Methylobacterium extorquens AM1 under oxic conditions. The enzyme was found to be a heterodimer of two subunits a1b1 of 107 and 61 kDa respectively. The purified enzyme contained per mol enzyme w 5 mol nonheme iron and acid-labile sulfur mol noncovalently bound FMN and w mol tungsten. The genes encoding the two subunits of FDH1 were identified on the M. extorquens AM1 chromosome next to each other in the order fdhlB fdhlA. Sequence comparisons revealed that the a-subunit harbours putative binding motifs for the molybdopterin cofactor and at least one iron-sulfur cluster. Sequence identity was highest to the catalytic subunits of the tungsten- and selenocysteine-containing formate dehydrogenases characterized from Eubacterium acidaminophilum and Moorella thermoacetica Clostridium thermoaceticum . The b-subunit of FDH1 contains putative motifs for binding FMN and NAD as well as an iron-sulfur cluster binding motif. The b-subunit appears to be a fusion protein with its N-terminal domain related to NuoE-like subunits and its C-terminal domain related to NuoF-like subunits of known NADH-ubiqui-none oxidoreductases. Keywords formate dehydrogenase methylotrophic bacteria one-carbon C1 metabolism tungsten molybdenum. The conversion of formate to CO2 is the terminal enzymatic step in C1 unit oxidation to CO2 in the .