The development of novel thiol reagents for probing ion channel structure

grantor: University of TorontoThiol reagents are designed to react with cysteine residues within ion channel proteins. In Part I, a novel thiol reagent, 2-(methylthiosulfonate)ethyl-' N'-('N,N'-dimethylaminoethyl)carbamate (MTSAC), was characterized when linked to the simple ion channel, gramicidin. MTSAC-treated channels showed a pattern of steps in the current recordings on the timescale of the carbamate bond isomerization; the size of the steps was sensitive to the location of the thiol-reactive site in relation to the channel entrance. MTSAC may be useful for establishing proximity to the pore in studies of ion channel protein structure. In the Part II, the synthesis of a group of lidocaine analogs was accomplished. A thiol-reactive lidocaine analog could be used to probe region surrounding the local anesthetic binding site in cysteine mutants of sodium channels. A group of lidocaine analogs was synthesized, with 2, 3, and 4 carbons linking the amino nitrogen and the thiol-reactive group.M.Sc