The Staphylococcal toxins leukocidin and γ-hemolysin consist of two protein components: F and S in leukocidin and Hγl and Hγll in γ-hemolysin. The two toxins share one component (F = Hγl). We found that the Hγll component was completely inactivated by the addition of monosialoganglioside GM1 at the molar ratio of 1:1. Disialogangliosides GD1a and GD1b had little effect on the inactivation of Hγll. The molar ratios of GD1a and GD1b to Hγll needed for maximum inactivation were 30:1 and 100:1, respectively. Related glycolipids caused little if any inactivation. Hγll bound to GM1 to form HγII-GM1 complexes.Analysis of the intrinsic aromatic amino acid fluorescence in Hγll and HγII-GM1 with 280 nm as the excitation wavelength showed that GM1 in the complex reduced the fluorescence intensity of Hγll by 12% without changing the wavelength of maximum emission (325 nm). We concluded that GM1 is a receptor of the Hγll component on human erythrocytes and that Hγll takes on a different conformation when it binds to GM1.
ASJC Scopus subject areas
- Analytical Chemistry
- Applied Microbiology and Biotechnology
- Molecular Biology
- Organic Chemistry