title: Structure of a 16 kDa integral membrane protein that has identity to the putative proton channel of the vacuolar H(+)-ATPase.
abstract: A 16 kDa protein has been isolated in a homogeneous form as the major component of a paracrystalline paired membrane structure closely resembling the gap junction. The primary structure of this protein from arthropod and vertebrate species has been determined by protein and cDNA sequencing. The amino acid sequences are highly conserved and virtually identical to the amino acid sequence of the proteolipid subunit of the vacuolar H(+)-ATPases. The disposition of the protein in the membrane has been studied using proteases and the N,N'-dicyclohexylcarbodiimide reactive site identified. These data, together with secondary structure predictions, suggest that the 16 kDa protein is for the most part buried in the membrane, arranged in a bundle of four hydrophobic alpha-helices. Using computer graphics, a model has been constructed based on this arrangement and on the electron microscopic images of the paracrystalline arrays.
authors.affiliation: Beatson Institute for Cancer Research, Glasgow, UK.
authors.forename: M E
authors.initials: ME
authors.lastname: Finbow
authors.forename: E E
authors.initials: EE
authors.lastname: Eliopoulos
authors.forename: P J
authors.initials: PJ
authors.lastname: Jackson
authors.forename: J N
authors.initials: JN
authors.lastname: Keen
authors.forename: L
authors.initials: L
authors.lastname: Meagher
authors.forename: P
authors.initials: P
authors.lastname: Thompson
authors.forename: P
authors.initials: P
authors.lastname: Jones
authors.forename: J B
authors.initials: JB
authors.lastname: Findlay
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D003001:Cloning, Molecular; D003461:Crystallography; D004024:Dicyclohexylcarbodiimide / Q000737:chemistry / Q000378:metabolism; D007473:Ion Channels / Q000737:chemistry* / Q000648:ultrastructure; D008099:Liver / Q000737:chemistry; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000737:chemistry* / Q000648:ultrastructure; D008854:Microscopy, Electron; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008121:Nephropidae; D011487:Protein Conformation; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000648:ultrastructure; D012689:Sequence Homology, Nucleic Acid
chemical_list: D007473:Ion Channels; D046911:Macromolecular Substances; D008565:Membrane Proteins; D004024:Dicyclohexylcarbodiimide; D006180:Proton-Translocating ATPases