Dark interaction of 5-methoxypsoralen and 8-methoxypsoralen with erythrocyte ghosts: a fluorescence and circular dichroism study.
The dark interaction of 5-methoxypsoralen (5-MOP) and 8-methoxypsoralen (8-MOP) with plasma membranes was studied using human erythrocyte ghosts as a model. In the presence of ghosts, modifications of the fluorescence characteristics of 5-MOP were observed, together with a quenching of the fluorescence of the tryptophan (Trp) residues of membrane proteins (up to 25%). Moreover, the appearance of an induced circular dichroism indicates that 5-MOP is located in a chiral environment. In contrast, only slight effects were observed in the case of 8-MOP. It is concluded that 5-MOP molecules are located partly within chiral protein sites of the membrane in such a way that a Förster energy transfer can occur from the Trp residues to the psoralen molecules.
Blais
J
J
Laboratoire de Physique et Chimie Biomoléculaire (CNRS URA 198), Paris, France.
Milhaud
J
J
Bolard
J
J
Vigny
P
P
D000078223:5-Methoxypsoralen; D002942:Circular Dichroism; D003624:Darkness; D004735:Energy Transfer; D004910:Erythrocyte Membrane / Q000737:chemistry / Q000187:drug effects*; D006801:Humans; D008730:Methoxsalen / Q000494:pharmacology*; D008954:Models, Biological; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000187:drug effects
D000078223:5-Methoxypsoralen; D014364:Tryptophan; D008730:Methoxsalen