Journal article

Identification of a membrane-spanning domain of the thiol-activated pore-forming toxin Clostridium perfringens perfringolysin O: An alpha-helical to beta-sheet transition identified by fluorescence spectroscopy

LA Shepard, AP Heuck, BD Hamman, J Rossjohn, MW Parker, KR Ryan, AE Johnson, RK Tweten

Biochemistry | AMER CHEMICAL SOC | Published : 1998


Clostridium perfringens perfringolysin O (PFO or theta-toxin) is a cytolytic toxin that binds to cholesterol-containing membranes and then self-associates to spontaneously form aqueous pores of varying size in the bilayer. In this study, a membrane-spanning domain has been identified in PFO by a combination of fluorescence spectroscopic methods using the fluorescent dye N, N'-dimethyl-N-(iodoacetyl)-N'-(7-nitrobenz-2-oxa-1, 3-diazolyl)ethylenediamine (NBD) whose emission properties are sensitive to water. PFO was substituted with a single cysteine at most of the residues between amino acids K189 and N218, and then each cysteine was modified with NBD. Each purified NBD-labeled PFO was then bo..

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