ATP binding site of P2X channel proteins: structural similarities with class II aminoacyl-tRNA synthetases.
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.
Freist
W
W
Max-Planck-Institut für experimentelle Medizin, Göttingen, Germany.
Verhey
J F
JF
Stühmer
W
W
Gauss
D H
DH
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*
D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate; D000604:Amino Acyl-tRNA Synthetases