title: Chiral recognition of D-kyotorphin by lipidic membranes: relevance toward improved analgesic efficiency.
abstract: D-Kyotorphin (D-KTP), the most potent isomer of the endorphin-like dipeptide kyotorphin (KTP), is a good drug candidate for the treatment of chronic pain and is thought to be involved in receptor-mediated processes. According to the "membrane catalysis" model, ligands interact with membrane lipids to attain high local concentrations in the receptor vicinity and to adopt the necessary conformation for docking. Therefore, the interaction and recognition of D-KTP by membranes is potentially important to its increased analgesic effect. In spite of the neutral net charge of D-KTP at pH 7.4, fluorescence spectroscopy reveals that the interaction with large unilamellar vesicles is more extensive than was observed for KTP. The tyrosine residue interacts extensively with rigid membranes, with a location and well-defined orientation in the bilayer. This suggests not only that D-KTP meets the structural constraints needed for receptor-ligand interaction in a manner similar to that of KTP, but also that the stronger membrane interaction and ability to discriminate rigid membrane domains might contribute to its improved analgesic effect.
authors.affiliation: Centro de Química-Física Molecular, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
authors.forename: Sílvia C D N
authors.initials: SC
authors.lastname: Lopes
authors.forename: Alexandre
authors.initials: A
authors.lastname: Fedorov
authors.forename: Miguel A R B
authors.initials: MA
authors.lastname: Castanho
mesh_terms: D000700:Analgesics / Q000737:chemistry* / Q000494:pharmacology; D004723:Endorphins / Q000737:chemistry* / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008051:Lipid Bilayers / Q000737:chemistry*; D008566:Membranes / Q000737:chemistry; D015394:Molecular Structure; D013050:Spectrometry, Fluorescence; D013237:Stereoisomerism; D014443:Tyrosine / Q000737:chemistry
chemical_list: D000700:Analgesics; D004723:Endorphins; D008051:Lipid Bilayers; C019448:kyotorphin; D014443:Tyrosine