Structural analysis of the fds operon encoding the NAD+-linked formate dehydrogenase of Ralstonia eutropha.
The fdsGBACD operon encoding the four subunits of the NAD+-reducing formate dehydrogenase of Ralstonia eutropha H16 was cloned and sequenced. Sequence comparisons indicated a high resemblance of FdsA (alpha-subunit) to the catalytic subunits of formate dehydrogenases containing a molybdenum (or tungsten) cofactor. The NH2-terminal region (residues 1-240) of FdsA, lacking in formate dehydrogenases not linked to NAD(P)+, exhibited considerable similarity to that of NuoG of the NADH:ubiquinone oxidoreductase from Escherichia coli as well as to HoxU and the NH2-terminal segment of HndD of NAD(P)+-reducing hydrogenases. FdsB (beta-subunit) and FdsG (gamma-subunit) are closely related to NuoF and NuoE, respectively, as well as to HoxF and HndA. It is proposed that the NH2-terminal domain of FdsA together with FdsB and FdsG constitute a functional entity corresponding to the NADH dehydrogenase (diaphorase) part of NADH:ubiquinone oxidoreductase and the hydrogenases. No significant similarity to any known protein was observed for FdsD (delta-subunit). The predicted product of fdsC showed the highest resemblance to FdhD from E. coli, a protein required for the formation of active formate dehydrogenases in this organism. Transcription of the fds operon is subject to formate induction. A promoter structure resembling the consensus sequence of sigma70-dependent promoters from E. coli was identified upstream of the transcriptional start site determined by primer extension analysis.
Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Grisebachstrasse 8, D-37077 Göttingen, Germany.
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D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D020118:Cupriavidus necator / Q000201:enzymology*; D017931:DNA Primers; D004583:Electrons; D005560:Formate Dehydrogenases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D008969:Molecular Sequence Data; D009243:NAD / Q000378:metabolism*; D009876:Operon; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D009243:NAD; D005560:Formate Dehydrogenases