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Tryptophan‐dependent sensitized photoinactivation of colicin E1 channels in bilayer lipid membranes
Author(s) -
Rokitskaya T.I.,
Zakharov S.D.,
Antonenko Yu.N.,
Kotova E.A.,
Cramer W.A.
Publication year - 2001
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(01)02811-3
Subject(s) - colicin , chemistry , lipid bilayer , biophysics , singlet oxygen , liposome , membrane , tryptophan , photosensitizer , bilayer , sodium azide , mutant , biochemistry , photochemistry , amino acid , escherichia coli , oxygen , biology , organic chemistry , gene
The bacterial toxin colicin E1 is known to induce voltage‐gated currents across a planar bilayer lipid membrane. In the present study, it is shown that the colicin‐induced current decreased substantially upon illumination of the membrane in the presence of the photosensitizer, aluminum phthalocyanine. This effect was almost completely abolished by the singlet oxygen quencher, sodium azide. Using single tryptophan mutants of colicin E1, Trp495 was identified as the amino acid residue responsible for the sensitized photodamage of the colicin channel activity. Thus, the distinct participation of a specific amino acid residue in the sensitized photoinactivation of a defined protein function was demonstrated. It is suggested that Trp495 is critical for the translocation and/or anchoring of the colicin channel domain in the membrane.