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Outer membrane protein A of Escherichia coli forms temperature‐sensitive channels in planar lipid bilayers
Author(s) -
Zakharian E,
Reusch R.N
Publication year - 2003
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/s0014-5793(03)01236-5
Subject(s) - conductance , escherichia coli , lipid bilayer , membrane , chemistry , bacterial outer membrane , crystallography , biophysics , biochemistry , biology , physics , condensed matter physics , gene
The temperature dependence of single‐channel conductance and open probability for outer membrane protein A (OmpA) of Escherichia coli were examined in planar lipid bilayers. OmpA formed two interconvertible conductance states, small channels, 36–140 pS, between 15 and 37°C, and large channels, 115–373 pS, between 21 and 39°C. Increasing temperatures had strong effects on open probabilities and on the ratio of large to small channels, particularly between 22 and 34°C, which effected sharp increases in average conductance. The data infer that OmpA is a flexible temperature‐sensitive protein that exists as a small pore structure at lower temperatures, but refolds into a large pore at higher temperatures.