Effect of lipids with different spontaneous curvature on the channel activity of colicin E1: evidence in favor of a toroidal pore.
The channel activity of colicin E1 was studied in planar lipid bilayers and liposomes. Colicin E1 pore-forming activity was found to depend on the curvature of the lipid bilayer, as judged by the effect on channel activity of curvature-modulating agents. In particular, the colicin-induced trans-membrane current was augmented by lysophosphatidylcholine and reduced by oleic acid, agents promoting positive and negative membrane curvature, respectively. The data obtained imply direct involvement of lipids in the formation of colicin E1-induced pore walls. It is inferred that the toroidal pore model previously validated for small antimicrobial peptides is applicable to colicin E1, a large protein that contains ten alpha-helices in its pore-forming domain.
A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia.
Alexander A
AA
Sobko
Elena A
EA
Kotova
Yuri N
YN
Antonenko
Stanislav D
SD
Zakharov
William A
WA
Cramer
D000595:Amino Acid Sequence; D003087:Colicins / Q000737:chemistry / Q000494:pharmacology*; D007473:Ion Channels / Q000378:metabolism*; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D008956:Models, Chemical; D019301:Oleic Acid / Q000494:pharmacology; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D003087:Colicins; D007473:Ion Channels; D008051:Lipid Bilayers; D008055:Lipids; D008081:Liposomes; D008244:Lysophosphatidylcholines; D019301:Oleic Acid