期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1981
卷号：78
期号：8
页码：4950-4954
DOI：10.1073/pnas.78.8.4950
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The cytotoxic effect of diphtheria toxin requires the entry of its enzymatic A fragment (Mr approximately 21,000) into the cytosol of sensitive cells. We show that the B45 fragment (Mr approximately 24,000) forms, in lipid bilayers, pores that are large enough (diameter greater than or equal to 18 A) to allow the passage of extended fragment A. Pore formation is maximal when the B45-containing side is at low pH (4.7) and the opposite side is at high pH (7.4). These conditions resemble the pH gradient existing across lysosomal membranes. We suggest that fragment A passes through these pores from acidic endocytotic vesicles (lysosomes?) to the cytosol.
