Oligomerisation of pneumolysin on cholesterol crystals: Similarities to the behaviour of polyene antibiotics

Pneumolysin is a cytolytic toxin of Streptococcus pneumoniae, a causative agent of pneumonia and meningitis. The prepore and pore states of pneumolysin have recently been investigated by cryo-electron microscopy and atomic force microscopy, confirming the existence of arc-shaped as well as ring-form oligomers. Here we provide further insights into the pneumolysin oligomer by studying the interaction of pneumolysin with cholesterol crystals, comparing the results to those obtained for polyene antibiotics, which also bind cholesterol.