An Inflammatory Polypeptide Complex from <i>Staphylococcus epidermidis</i>: Isolation and Characterization

Staphylococcus epidermidis releases factors that activate the HIV-1 long terminal repeat, induce cytokine release, and activate nuclear factor κB in cells of macrophage lineage. The active material had a mass of 34,500 daltons, was inactivated by proteases and partitioned into the phenol layer on hot aqueous phenol extraction, and thus was termed phenol-soluble modulin (PSM). High performance liquid chromatography (HPLC) of crude PSM yielded two peaks of activity designated PSM peak 1 and peak 2. MALDI-TOF (matrix-assisted laser desorption ionization-time of flight) mass spectroscopy indicated the presence of two components in peak 1, which were designated PSMα and PSMβ. Peak 2 contained a single component, designated PSMγ. Separation of PSMα and PSMβ in peak 1 could be achieved by a second HPLC procedure. The structure of each component was determined by amino acid sequence analysis and identification and sequencing of their genes. PSMα, PSMβ, and PSMγ were 22-, 44-, and 25-amino acid, respectively, strongly hydrophobic polypeptides. PSMγ was identified as Staphylococcus epidermidis delta toxin, whereas PSMα and PSMβ exhibited more distant homology to previously described staphylo