Dynamic properties of the colicin E1 ion channel.
The mechanism of channel formation and action of channel-forming colicins is a paradigm for the study of dynamic aspects of membrane-protein interactions. The following experimental results concerning interaction of the colicin E1 channel domain with target membranes, in vitro and in vivo, are discussed: (1) the nature of the translocation-competent state of the channel-forming domain; (2) unfolding of the colicin channel peptide during in vitro binding and anchoring of the channel to liposome membranes at acidic pH; (3) reversal of channel peptide binding to liposomes by an alkaline-directed pH shift; (4) voltage-driven translocation and gating of the ion channel, discussed in the context of a four-helix model for a monomeric channel; (5) rescue of colicin-treated cells by high levels of external K+; (6) trypsin rescue of cells depolarized by the colicin ion channel; and (7) interaction of the channel domain with its immunity protein.
Cramer
W A
WA
Department of Biological Sciences, Lilly Hall of Life Sciences, Purdue University, West Lafayette, IN.
Zhang
Y L
YL
Schendel
S
S
Merrill
A R
AR
Song
H Y
HY
Stauffacher
C V
CV
Cohen
F S
FS
D000595:Amino Acid Sequence; D001692:Biological Transport; D003087:Colicins / Q000737:chemistry* / Q000633:toxicity; D006863:Hydrogen-Ion Concentration; D007473:Ion Channels / Q000187:drug effects*; D008565:Membrane Proteins / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D011188:Potassium / Q000494:pharmacology; D011487:Protein Conformation
D003087:Colicins; D007473:Ion Channels; D008565:Membrane Proteins; D011188:Potassium