Chloroethylclonidine Binds Irreversibly to Exposed Cysteines in the Fifth Membrane-Spanning Domain of the Human α2A-Adrenergic Receptor
摘要:
The α2-adrenergic receptors (α2-ARs) mediate signals to intracellular second messengers via guanine nucleotide binding proteins. Three human genes encoding α2-AR subtypes (α2A, α2B, α2C) have been cloned. Several chemical compounds display subtype differences in their binding and/or functional activity. Site-directed mutagenesis and molecular modeling are new tools with which to investigate the subtype selectivity of ligands. In this study, we introduce a new approach to mapping of the binding site crevice of the human α2A-AR. Based on a three-dimensional receptor model, we systematically mutated residues 197–201 and 204 in the fifth transmembrane domain of the human α2A-AR to cysteine. Chloroethylclonidine, an alkylating derivative of the α2-adrenergic agonist clonidine, binds irreversibly to α2A-ARs by forming a covalent bond with the sulfhydryl side chain of a cysteine residue exposed in the binding cavity, leading to inactivation of the receptor. Irreversible binding of chloroethylclonidine was used as a criterion for identifying introduced cysteine residues as being exposed in the binding cavity. The results supported a receptor model in which the fifth transmembrane domain is α-helical, with residues Val197, Ser200, Cys201, and Ser204 exposed in the binding pocket. Residues Ile198, Ser199, Ile202, and Gly203 face the lipid bilayer of the plasma membrane. This approach emerges as a powerful tool for structural characterization of the α2-ARs.
Composition de mise en forme des cheveux comprenant au moins une imine hors hydroxyde
申请人:L'OREAL
公开号:EP1532960A1
公开(公告)日:2005-05-25
L'invention a pour objet une composition cosmétique de mise en forme permanente des fibres kératiniques prête à l'emploi contenant, en tant qu'agent actif de mise en forme permanente, une imine n'appartenant pas à la famille des hydroxydes. Elle vise également un kit contenant des compartiments à mettre en contact pour former la composition prête à l'emploi, ainsi qu'un procédé mettant en oeuvre cette composition.
Composition de défrisage des cheveux comprenant au moins une imine hors hydroxyde
申请人:L'OREAL
公开号:EP1532963A1
公开(公告)日:2005-05-25
L'invention a pour objet une composition cosmétique de défrisage des fibres kératiniques prête à l'emploi, le milieu cosmétiquement acceptable étant exempt d'alcane polyhydroxylé, contenant, en tant qu'agent actif de défrisage, une imine n'appartenant pas à la famille des hydroxydes. Elle vise également un kit contenant des compartiments à mettre en contact pour former la composition prête à l'emploi, ainsi qu'un procédé mettant en oeuvre cette composition.
Hair shaping composition comprising at least one non-hydroxide imine
申请人:Malle Gerard
公开号:US20050129645A1
公开(公告)日:2005-06-16
The disclosure relates to ready-to-use cosmetic compositions for permanently shaping keratin fibers comprising, as a permanent hair-shaping active agent, an imine not belonging to the hydroxide family. The disclosure also provides kits comprising compartments to be placed in contact to form the ready-to-use compositions, and processes using these compositions.
Hair relaxing composition comprising at least one non-hydroxide imine
申请人:Malle Gerard
公开号:US20050136017A1
公开(公告)日:2005-06-23
The disclosure provides ready-to-use cosmetic compositions for relaxing keratin fibers in a cosmetically acceptable medium free of polyhydroxylated alkane, containing, as a relaxing agent, an imine not belonging to the hydroxide family. The disclosure also provides kits containing compartments to be placed in contact to form the ready-to-use compositions, and processes using these compositions.