Photodynamic inactivation of an ion channel: gramicidin A.
The ion channel formed by the peptide gramicidin A in planar lipid membranes is inactivated by visible light in the presence of the photosensitizer Rose Bengal. This is concluded from the strong decrease of the membrane conductance by more than two orders of magnitude. Experiments performed at different oxygen concentrations, in the presence of the singlet oxygen quenchers beta-carotene or alpha-tocopherol indicate, that presumably a type I process between the dye Rose Bengal and the tryptophan residues of the gramicidin channel with a subsequent oxidation of the tryptophans is responsible for the loss of the conductance properties of the channel.
Strässle
M
M
Fakultät für Biologie, Universität Konstanz, Fed. Rep. Germany.
Stark
G
G
D000595:Amino Acid Sequence; D006096:Gramicidin / Q000737:chemistry / Q000528:radiation effects*; D007473:Ion Channels / Q000737:chemistry / Q000187:drug effects / Q000528:radiation effects*; D008027:Light; D008969:Molecular Sequence Data; D010777:Photochemistry; D012395:Rose Bengal / Q000494:pharmacology
D007473:Ion Channels; D006096:Gramicidin; D012395:Rose Bengal