title: The Staphylococcus aureus leucine aminopeptidase is localized to the bacterial cytosol and demonstrates a broad substrate range that extends beyond leucine.
abstract: Staphylococcus aureus is a potent pathogen of humans exhibiting a broad disease range, in part due to an extensive repertoire of secreted virulence factors, including proteases. Recently, we identified the first example of an intracellular protease (leucine aminopeptidase, LAP) that is required for virulence in S. aureus. Disruption of pepZ, the gene encoding LAP, had no affect on the growth rate of bacteria; however, in systemic and localized infection models the pepZ mutant had significantly attenuated virulence. Recently, a contradictory report was published suggesting that LAP is an extracellular enzyme and it is required for growth in S. aureus. Here, we investigate these results and confirm our previous findings that LAP is localized to the bacterial cytosol and is not required for growth. In addition, we conduct a biochemical investigation of purified recombinant LAP, identifying optimal conditions for enzymatic activity and substrate preference for hydrolysis. Our results show that LAP has a broad substrate range, including activity against the dipeptide cysteine-glycine, and that leucine is not the primary target of LAP.
authors.affiliation: Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL 33620, USA.
authors.forename: Ronan K
authors.initials: RK
authors.lastname: Carroll
authors.forename: Florian
authors.initials: F
authors.lastname: Veillard
authors.forename: Danielle T
authors.initials: DT
authors.lastname: Gagne
authors.forename: Jarrod M
authors.initials: JM
authors.lastname: Lindenmuth
authors.forename: Marcin
authors.initials: M
authors.lastname: Poreba
authors.forename: Marcin
authors.initials: M
authors.lastname: Drag
authors.forename: Jan
authors.initials: J
authors.lastname: Potempa
authors.forename: Lindsey N
authors.initials: LN
authors.lastname: Shaw
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D018441:Biofilms / Q000187:drug effects; D015153:Blotting, Western; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D006868:Hydrolysis / Q000187:drug effects; D042541:Intracellular Space / Q000201:enzymology; D007930:Leucine / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D007931:Leucyl Aminopeptidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008670:Metals / Q000494:pharmacology; D011994:Recombinant Proteins / Q000378:metabolism; D013211:Staphylococcus aureus / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development / Q000502:physiology; D013379:Substrate Specificity / Q000187:drug effects
chemical_list: D001426:Bacterial Proteins; D008670:Metals; D011994:Recombinant Proteins; D007931:Leucyl Aminopeptidase; D007930:Leucine; C012211:ubenimex