Action of diphtheria toxin does not depend on the induction of large,stable pores across biological membranes |
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Authors: | G. M. Alder C. L. Bashford C. A. Pasternak |
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Affiliation: | (1) Division of Biochemistry, Department of Cellular and Molecular Sciences, St. George's Hospital Medical School, SW17 ORE London, England |
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Abstract: | Summary Vero cells exposed to diphtheria toxin at pH 4.5 leak monovalent cations but not amino acids or phosphorylated metabolites; affected cells do not take up trypan blue. Monovalent cation leakage is inhibited by 1mmCd2+, but not by 1mmZn2+ or Ca2+. Cd2+ blocks calcein leakage from liposomes and closes diphtheria toxin-induced channels in lipid bilayers. It is concluded that translocation of the A fragment of diphtheria toxin across biological membranes does not depend on the formation of large stable pores, but that small Cd2+-sensitive pores may play a role. |
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Keywords: | diphtheria toxin planar bilayers liposomes Vero cells cadmium (Cd2+) |
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