Monomer-monomer interactions drive the prepore to pore conversion of a beta-barrel-forming cholesterol-dependent cytolysin. |
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Authors: | Eileen M Hotze Alejandro P Heuck Daniel M Czajkowsky Zhifeng Shao Arthur E Johnson Rodney K Tweten |
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Institution: | Department of Microbiology and Immunology, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA. |
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Abstract: | Perfringolysin O (PFO), a cholesterol-dependent cytolysin, forms large oligomeric pore complexes comprised of up to 50 PFO molecules. In the present studies a mutant of PFO (PFO(Y181A)) has been identified that traps PFO in a multimeric prepore complex that cannot insert its transmembrane beta-hairpins and therefore cannot form a pore. Remarkably, PFO(Y181A) can be induced to insert its transmembrane beta-hairpins if functional PFO is incorporated into the PFO(Y181A) oligomeric prepore complex. Furthermore, the transition from prepore to pore appears to be an "all or none" process; partial insertion of the transmembrane beta-barrel does not occur. Therefore, cooperative interactions between the monomers of the prepore drive the prepore to pore conversion that results in the formation of the transmembrane beta-barrel. |
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