The F420H2-dehydrogenase from Methanolobus tindarius: cloning of the ffd operon and expression of the genes in Escherichia coli

The membrane-bound F420H2-dehydrogenase from the methylotrophic methanogen Methanolobus tindarius oxidizes reduced coenzyme F-420 and feeds the electr ons into an energy-conserving electron transport chain. Based on the N-term inal amino acid sequence of the 40-kDa subunit of F420H2-dehydrogenase the corresponding gene ffdB was detected in chromosomal DNA of M. tindarius. Se quence analysis, primer extension. and RT-PCR experiments indicated that ff dB is part of an operon harboring three additional open reading frames (ffd A,ffdC,ffdD). The corresponding mRNA transcript and transcription start sit es were determined. All four genes could be heterologously expressed in Esc herichia coli. (C) 1999 Federation of European Microbiological Societies. P ublished by Elsevier Science B.V. All rights reserved.