THE 2 STAPHYLOCOCCAL BICOMPONENT TOXINS, LEUKOCIDIN AND GAMMA-HEMOLYSIN, SHARE ONE-COMPONENT IN COMMON

Staphylococcal bi-component toxins, leukocidin and gamma-hemolysin, consist of two protein components, i.e. F and S for leukocidin and HgammaI and HgammaII for gamma-hemolysin. In this study we purified HgammaI and HgammaII to homogeneity from the culture medium of Staphylococcus aureus RIMD 310925 and compared their properties with those of F and S purified from the same source. The N-terminal 59- and C-terminal 2-residue amino acid sequences, apparent molecular mass, and isoelectric point of purified HgammaI were the same as those of F. In an Ouchterlony double diffusion test a fused line without spur was formed between F and HgammaI using either anti-F or anti-HgammaI antibodies. A synergistic action of F and HgammaII caused hemolysis of human red blood cells, and HgammaI acted synergistically with S to exhibit leukocidin activity. We conclude that the two toxins share one protein component (F = HgammaI) in common and leukocidin- and gamma-hemolysin-specific activities are determined by S and HgammaII, respectively. It is also reported that the N-terminal 58-residue sequence of HgammaII is 72% similar to the corresponding sequence of S.