title: ATP binding site of P2X channel proteins: structural similarities with class II aminoacyl-tRNA synthetases.
abstract: The extracellular loop of P2X channel proteins contains a sequence stretch (positions 170-330) that exhibits similarities with the catalytic domains of class II aminoacyl-tRNA synthetases as shown by secondary structure predictions and sequence alignments. The arrangement of several conserved cysteines (positions 110-170) shows similarities with metal binding regions of metallothioneins and zinc finger motifs. Thus, for the extracellular part of P2X channel proteins a metal binding domain and an antiparallel six-stranded beta-pleated sheet containing the ATP binding site are very probable. The putative channel forming H5 part (positions 320-340) shows similarities with the enzyme motif 1 responsible for aggregation of subunits to the holoenzyme.
authors.affiliation: Max-Planck-Institut für experimentelle Medizin, Göttingen, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Freist
authors.forename: J F
authors.initials: JF
authors.lastname: Verhey
authors.forename: W
authors.initials: W
authors.lastname: Stühmer
authors.forename: D H
authors.initials: DH
authors.lastname: Gauss
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry* / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D018048:Receptors, Purinergic P2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate; D000604:Amino Acyl-tRNA Synthetases