期刊
NANO LETTERS
卷 16, 期 12, 页码 7915-7924出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.nanolett.6b04219
关键词
Atomic force microscopy; transmembrane pore formation; cholesterol-dependent cytolysins (CDC); electron microscopy; supported lipid membranes; X-ray crystallography
类别
资金
- Max Planck Society
- Frankfurt International Max Planck Research School
- Swiss National Science Foundation [205320_160199]
- European Union Marie Curie Actions program through the ACRITAS Initial Training Network (FP7-PEOPLE-ITN) [317348]
- Swiss National Science Foundation (SNF) [205320_160199] Funding Source: Swiss National Science Foundation (SNF)
Pneumolysin (PLY) is the main virulence factor of Streptococcus pneumoniae that causes pneumonia, meningitis, and invasive pneumococcal infection. PLY is produced as monomers, which bind to cholesterol-containing membranes, where they oligo-merize into large pores. To investigate the pore-forming mechanism, we determined the crystal structure of PLY at 2.4 angstrom and used it to design mutants on the surface of monomers. Electron microscopy of liposomes incubated with PLY mutants revealed that several mutations interfered with ring formation. Mutants that formed incomplete rings or linear arrays had strongly reduced hemolytic activity. By high-resolution time-lapse atomic force microscopy of wild-type PLY, we observed two different ring-shaped complexes. Most of the complexes protruded similar to 8 nm above the membrane surface, while a smaller number protruded similar to 11 nm or more. The lower complexes were identified as pores or prepores by the presence or absence of a lipid bilayer in their center. The taller complexes were side-by-side assemblies of monomers of soluble PLY that represent an early form of the prepore. Our observations suggest a four-step mechanism of membrane attachment and pore formation by PLY, which is discussed in the context of recent structural models. The functional separation of these steps is necessary for the understanding how cholesterol-dependent cytolysins form pores and lyse cells.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据