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Measuring kinetic drivers of pneumolysin pore structure
Robert J C Gilbert1, Andreas F-P Sonnen2
1Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK. gilbert@strubi.ox.ac.uk.
European Biophysics Journal : EBJ
|February 25, 2016
Summary
Pneumolysin, a pore-forming protein, creates cell damage through variable-sized structures. Its assembly mechanism depends on protein concentration, influencing arc and full ring formation for distinct biological roles.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Membrane attack complex-perforin/cholesterol-dependent cytolysin (MACPF/CDC) proteins assemble into pores.
- Pore formation involves pre-pore oligomers transitioning to pores, forming rings or arcs.
Purpose of the Study:
- Investigate pneumolysin pore formation kinetics in red blood cells.
- Elucidate the concentration-dependent mechanisms of MACPF/CDC pore assembly.
Main Methods:
- Utilized a kinetic assay to monitor red blood cell lysis.
- Analyzed pneumolysin concentration-dependent pore formation.
Main Results:
- Cell lysis showed dual concentration dependence: lower concentrations rely on cooperative arc oligomerization, higher concentrations on membrane-bound protein affinity for cholesterol.
- A lag phase before lysis was dependent on pneumolysin oligomerization.
Conclusions:
- Pneumolysin pore formation is a concentration-dependent, cooperative process.
- MACPF/CDCs can form variable-sized oligomeric structures with potential distinct biological functions.
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