The Helicobacter felis ftsH gene encoding an ATP-dependent metalloprotease can replace the Escherichia coli homologue for growth and phage lambda lysogenization.

Cloning and sequencing of an approximately 6.0-kb chromosomal DNA fragment from Helicobacter felis revealed five complete open reading frames. The deduced amino acid sequence of one ORF exhibited sequence similarity to the FtsH protein, an ATP-dependent metalloprotease, from various bacterial species. The encoded protein consists of 638 amino acid residues with a molecular mass of 70.2 kDa. The hydropathy profile of the FtsH protein predicted two N-terminal transmembrane regions that were confirmed experimentally. Insertion of ftsH into a new versatile expression vector resulted in overexpression of FtsH protein in Escherichia coli. In addition, the E. coli ftsH gene could be replaced by the H. felis homologue to allow reduced growth and tenfold increased lysogenization by temperate phage lambda.