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Is the mammalian porin channel, VDAC, a perfect cylinder in the high conductance state?
Author(s) -
Carneiro C.M.M,
Krasilnikov O.V,
Yuldasheva L.N,
Campos de Carvalho A.C,
Nogueira R.A
Publication year - 1997
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(97)01198-8
Subject(s) - porin , conductance , voltage dependent anion channel , channel (broadcasting) , biophysics , ion channel , geometry , membrane , chemistry , lipid bilayer , materials science , bacterial outer membrane , physics , electrical engineering , biology , mathematics , biochemistry , condensed matter physics , engineering , receptor , escherichia coli , gene
The mammalian porin channel (VDAC, porin‐31BM) was reconstituted in planar lipid bilayers under voltage clamp conditions. The radii of both entrances of the channel were examined using a method that consisted in filling the channel with different non‐electrolytes through its cis or trans entrances while recording single channel conductances. As a result it was found that the geometry of channels formed by porin‐31BM could not be approximated by a perfectly cylindrical pore. In fact there is an asymmetry in the geometry of the channel: the diameters of the cis and trans entrances were estimated to be ∼2 nm and ∼4 nm respectively.