Analysis of the vhoGAC and vhtGAC operons from Methanosarcina mazei strain Gö1, both encoding a membrane-bound hydrogenase and a cytochrome b.

摘要: DNA encompassing the structural genes of two membrane-bound hydrogenases from Methanosarcina mazei Go1 was cloned and sequenced. The genes, arranged in order vhoG vhoA as well vhtG vhtA, were identified those encoding small large subunits NiFe [Deppenmeier, U., Blaut, M., Schmidt, B. & Gottschalk, G. (1992) Arch. Microbiol. 157, 505-511]. Northern-blot analysis revealed that formed part operons, both containing one additional open reading frame (vhoC vhtC) which codes for a cytochrome b. This conclusion drawn homology deduced N-terminal amino acid sequences vhoC vhtC N-terminus 27-kDa isolated Ms. C16. VhoC VhtC contain four tentative hydrophobic segments might span cytoplasmic membrane. Hydropathy plots suggest His23 His50 are involved heme coordination. comparison sequencing data with experimentally determined subunit indicate presence 48-amino-acid leader peptide front polypeptides. VhoA VhtA contained conserved sequence DPCXXC C-terminal region, excludes selenocysteine residue these hydrogenases. Promoter found upstream vhtG, respectively. Downstream vhoC, putative terminator identified. Alignments gene clusters vhoGAC vhtGAC showed 92-97% identity. Only C-termini not similar.