SEQUENCE-ANALYSIS AND INTERPOSON MUTAGENESIS OF THE HUPT GENE, WHICH ENCODES A SENSOR PROTEIN INVOLVED IN REPRESSION OF HYDROGENASE SYNTHESIS IN RHODOBACTER-CAPSULATUS
S. Elsen et al., SEQUENCE-ANALYSIS AND INTERPOSON MUTAGENESIS OF THE HUPT GENE, WHICH ENCODES A SENSOR PROTEIN INVOLVED IN REPRESSION OF HYDROGENASE SYNTHESIS IN RHODOBACTER-CAPSULATUS, Journal of bacteriology, 175(22), 1993, pp. 7404-7412
The hupT gene, which represses hydrogenase gene expression in the purp
le photosynthetic bacterium Rhodobacter capsulatus, has been identifie
d and sequenced. The nucleotide sequence of hupT and of the contiguous
downstream open reading frame, hupU, is reported. The HupT protein of
456 amino acids (48,414 Da) has sequence similarity with the FixL, Dc
tB, NtrB, and ArcB proteins and is predicted to be a soluble sensor ki
nase. Insertional inactivation of the hupT gene led to deregulation of
transcriptional control, so that the hydrogenase structural operon hu
pSLC became overexpressed in cells grown anaerobically or aerobically.
The HupT- mutants were complemented in trans by a plasmid containing
an intact copy of the hupT gene. The hupU open reading frame, capable
of encoding a protein of 84,879 Da, shared identity with [NiFe]hydroge
nase subunits; the strongest similarity was observed with the periplas
mic hydrogenase of Desulfovibrio baculatus.