Partial oligomerization of pyolysin induced by a disulfide-tethered mutant

  1. Get@NRC: Partial oligomerization of pyolysin induced by a disulfide-tethered mutant (Opens in a new window)
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Journal titleBiochemistry and Cell Biology
Pages709717; # of pages: 9
SubjectBacterial toxin; Cholesterol-dependent cytolysins; Disulfide bonds; Equimolar mixtures; Hybrid oligomers; Membrane insertion; Pore formation; Protein activity; Pyolysin; Trans-membrane pores; Wild types; Cholesterol; Covalent bonds; Lipid bilayers; Membranes; Oligomerization; Pore size; Proteins; Sulfur compounds; Oligomers; bacterial toxin; disulfide; pyolysin; unclassified drug; Arcanobacterium pyogenes; article; bacterial mutation; bacterium mutant; channel gating; complex formation; controlled study; Escherichia coli; gene insertion; hemolysis; oligomerization; Bacterial Proteins; Bacterial Toxins; Binding Sites; Cell Membrane; Cytotoxins; Disulfides; Hemolysin Proteins; Mutation; Polymerization; Protein Conformation; Protein Subunits; Bacteria (microorganisms)
AbstractThe bacterial toxin pyolysin (PLO) belongs to the family of cholesterol-dependent cytolysins (CDCs), which form large, ring-shaped oligomeric pores in cholesterol-containing membranes. Monomeric CDC molecules have a structure of four domains, with domains 2 and 3 packed against each other. After binding to target membranes containing cholesterol, toxin monomers oligomerize into pre-pore complexes. Trans-membrane pores form when the pre-pores insert into the lipid bilayer. Membrane insertion requires each subunit in the pre-pore to undergo a significant change in conformation, including the separation of domains 2 and 3. We here characterize a pyolysin mutant with an engineered disulfide bond between domains 2 and 3. The disulfide-tethered mutant binds to membranes but does not form oligomers. When mixed with wild type PLO, the two proteins form hybrid oligomers, which are reduced in size and arc-shaped rather than ring-shaped. With equimolar mixtures or the disulfide mutant in slight excess, the hybrid oligomers retain pore-forming activity, while a larger excess of the mutant suppresses pore formation. These results support a "partially cooperative" mode of protein activity, in which a limited number of functional subunits within an oligomer have to cooperate to initiate membrane insertion and pore formation. © 2012 Published by NRC Research Press.
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AffiliationNational Research Council Canada (NRC-CNRC); NRC Biotechnology Research Institute (BRI-IRB)
Peer reviewedYes
NPARC number21269252
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Record identifier823501d5-556d-4029-bce5-fad85173dea8
Record created2013-12-12
Record modified2016-05-09
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