Monomer-monomer interactions propagate structural transitions necessary for pore formation by the cholesterol-dependent cytolysins.
The assembly of the cholesterol-dependent cytolysin (CDC) oligomeric pore complex requires a complex choreography of secondary and tertiary structural changes in domain 3 (D3) of the CDC monomer structure. A point mutation was identified in the archetype CDC, perfringolysin O, that blocks detectable D3 structural changes and traps the membrane-bound monomers in an early and reversible stage of oligomer assembly. Using this and other mutants we show that specific D3 structural changes are propagated from one membrane-bound monomer to another. Propagation of these structural changes results in the exposure of a β-strand in D3 that allows it to pair and form edge-on interactions with a second β-strand of a free membrane-bound monomer. Pairing of these strands establishes the final geometry of the pore complex and is necessary to drive the formation of the β-barrel pore. These studies provide new insights into how structural information is propagated between membrane-bound monomers of a self-assembling system and the interactions that establish the geometry of the final pore complex.
Department of Microbiology and Immunology, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA.
Eileen M
EM
Hotze
Elizabeth
E
Wilson-Kubalek
Allison J
AJ
Farrand
Lori
L
Bentsen
Michael W
MW
Parker
Arthur E
AE
Johnson
Rodney K
RK
Tweten
D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D031541:Fluorescence Resonance Energy Transfer; D006461:Hemolysis; D006801:Humans; D008854:Microscopy, Electron; D054353:Perforin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017354:Point Mutation / Q000235:genetics; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D054353:Perforin; D002784:Cholesterol