The Legionella pneumophila major secretory protein, a protease, is not required for intracellular growth or cell killing.

摘要: The Legionella pneumophila major secretory protein (Msp) is a Zn2+ metalloprotease whose function in pathogenesis unknown. structural gene for the Msp protease, mspA, was isolated from an L. genomic library. In Escherichia coli which contain plasmids with mspA gene, and activity are found periplasmic space cytoplasm. Transposon mutagenesis Tn9 of mspA-containing plasmid E. yielded mutants no longer expressed protease others increased activity. These results suggested that expression might be regulated. shown to produced at much higher level grown rich compared semidefined media. A insertion abolishes introduced into genome. This mspA::Tn9 strain showed detectable production by immunoblot analysis, it had less than 0.1% wild-type strain. mutant fully capable growing within killing human macrophages derived HL-60 cell line.