Open AccessSingle channel evidence for innate pore‐formation by Vibrio parahaemolyticus thermostable direct haemolysin (TDH) in phospholipid bilayers
Author(s) -
Hardy Simon P.,
Nakano Masayuki,
Iida Tetsuya
Publication year - 2004
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/j.femsle.2004.09.015
Subject(s) - vibrio parahaemolyticus , hemolysin , phospholipid , microbiology and biotechnology , vibrionaceae , chemistry , biology , membrane , bacteria , biochemistry , gene , genetics , virulence
Vibrio parahaemolyticus thermostable direct haemolysin (TDH) is widely considered to be a pore‐forming toxin. The protein has no significant homology to other known pore‐forming toxins and its mechanism of action in vivo remains undefined. We demonstrate single channel pore‐forming activity of V. parahaemolyticus TDH in planar lipid bilayers. Channel conductance ranged between 30–450 pS in 0.5 M KCl with a calculated cation selectivity (P K /P Cl ) of 2.7. Channels were formed in NaCl and choline‐Cl with and without cholesterol present and in the presence of neutral or negatively charged phospholipids. Zinc ions did not block pore formation. Whilst various techniques have previously suggested that TDH is a pore‐forming toxin, the data in this study provide direct single channel evidence and indicate several features of pore formation in synthetic phospholipid membranes.