title: Structural motif and characteristics of the extracellular domain of P2X receptors.
abstract: Seven sequences of the proteins recently cloned from rat tissues and identified as P2X receptors are examined. Their putative transmembrane and extracellular domains and the most probable locations of disulphide bridges are discussed. Some surface accessible regions are identified and the structure of the putative ATP binding domain is discussed in the light of known selectivities and physiological characteristics of individual P2X subunits. The summarised information and the theoretical considerations regarding the protein structure of P2X receptors have been used to select amino acid sequences for raising antibodies against the P2X1 receptor subunit. Initial results suggest that, in rat brainstem, P2X1 receptor subunits are found on a distinct subpopulation of neuronal perikarya in distributions consistent with distributions of known alpha,beta-methylene-ATP autoradiography and physiological effects of purinoceptor activation.
authors.affiliation: Institute for Biomedical Research, Department of Anatomy, The University of Sydney, New South Wales, Australia.
authors.forename: M A
authors.initials: MA
authors.lastname: Hansen
authors.forename: J A
authors.initials: JA
authors.lastname: Barden
authors.forename: V J
authors.initials: VJ
authors.lastname: Balcar
authors.forename: K A
authors.initials: KA
authors.lastname: Keay
authors.forename: M R
authors.initials: MR
authors.lastname: Bennett
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001923:Brain Chemistry; D002462:Cell Membrane / Q000737:chemistry; D004563:Electrochemistry; D005110:Extracellular Space / Q000737:chemistry*; D008969:Molecular Sequence Data; D009474:Neurons / Q000737:chemistry; D010710:Phosphates / Q000378:metabolism; D017433:Protein Structure, Secondary; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000737:chemistry*; D058469:Receptors, Purinergic P2X; D058476:Receptors, Purinergic P2X2; D058477:Receptors, Purinergic P2X3; D058848:Receptors, Purinergic P2X4; D058486:Receptors, Purinergic P2X7; D016415:Sequence Alignment; D014018:Tissue Distribution
chemical_list: C546403:P2rx2 protein, rat; C546410:P2rx3 protein, rat; C548228:P2rx4 protein, rat; C546470:P2rx7 protein, rat; D010710:Phosphates; D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X; D058476:Receptors, Purinergic P2X2; D058477:Receptors, Purinergic P2X3; D058848:Receptors, Purinergic P2X4; D058486:Receptors, Purinergic P2X7; D000255:Adenosine Triphosphate