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Native and chemically modified porin channels from Salmonella typhi Ty2 in planar lipid bilayers
Author(s) -
Labarca Pedro,
Lobos Sergio,
Calderón Inés,
Mora Guido
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)80328-3
Subject(s) - porin , chemistry , conductance , bacterial outer membrane , membrane , lipid bilayer , salmonella typhi , biophysics , crystallography , biochemistry , biology , physics , escherichia coli , gene , condensed matter physics
Native porins, from Salmonella typhi Ty2 outer membrane, and porins alkylated with pyridoxal phosphate (Plp) were studied in planar lipid bilayers. The conductance of bilayers exposed to native or chemically modified porins increases in discrete jumps. Conductance histograms for native porins displayed two major peaks at 1.7 and 6.7 nS (in 0.5 M KCl). On the other hand, Plp‐treated porins exhibited a single major peak at 1 nS. The relation between bilayer conductance and native porin concentration was linear. However, this relation became logarithmic in the presence of modified porins. The results support the notion that alkaline reduction of S. typhi Ty2 porins with Plp dissociates porin channel trimers in a reversible fashion.