The Staphylococcus aureus secretome - TI Pharma

Chapter 9
sequence of B. licheniformis DSM 13, 296 proteins were predicted to contain an N-terminal
signal peptide for secretion via the Sec system. Using 2-D PAGE, the extracellular proteome
of B. licheniformis grown in different media was studied. From the approximately 200 spots
visible on the gels, 89 were identified that either contain an N-terminal signal sequence or are
known to be secreted by other mechanisms than the Sec pathway. The extracellular proteome
of B. licheniformis was shown to include proteins from different functional classes, like
enzymes for the degradation of macromolecules, proteins involved in cell wall turnover,
flagellum- and phage-related proteins and some proteins of yet unknown function. Protein
secretion was shown to be highest during the stationary growth phase. Furthermore, cells
grown in a complex medium were found to secrete considerably higher protein amounts than
cells grown in a minimal medium. Limitation of phosphate, carbon and nitrogen sources
resulted in the secretion of specific proteins that may be involved in counteracting the
potentially negative effects of the respective starvation.
In conclusion, comparative secretomics approaches are applicable to the functional dissection
of secretomes of bacterial pathogens, such as S. aureus, and biotechnologically relevant cell
factories, such as B. subtilis and B. licheniformis.
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