title: The structure of the third intracellular loop of the muscarinic acetylcholine receptor M2 subtype.
abstract: We have examined whether the long third intracellular loop (i3) of the muscarinic acetylcholine receptor M2 subtype has a rigid structure. Circular dichroism (CD) and nuclear magnetic resonance spectra of M2i3 expressed in and purified from Escherichia coli indicated that M2i3 consists mostly of random coil. In addition, the differential CD spectrum between the M2 and M2deltai3 receptors, the latter of which lacks most of i3 except N- and C-terminal ends, gave no indication of secondary structure. These results suggest that the central part of i3 of the M2 receptor has a flexible structure.
authors.affiliation: Institute for Biomolecular Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Ichiyama
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Oka
authors.forename: Kazuko
authors.initials: K
authors.lastname: Haga
authors.forename: Shuichi
authors.initials: S
authors.lastname: Kojima
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Tateishi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shirakawa
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Haga
mesh_terms: D000818:Animals; D002942:Circular Dichroism; D004926:Escherichia coli; D015870:Gene Expression; D006801:Humans; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D043585:Receptor, Muscarinic M2 / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D043585:Receptor, Muscarinic M2