Related Experiment Video
Updated: Jul 11, 2026

Proteomics to Identify Proteins Interacting with P2X2 Ligand-Gated Cation Channels
Published on: May 19, 2009
ATP binding site of P2X channel proteins: structural similarities with class II aminoacyl-tRNA synthetases
W Freist1, J F Verhey, W Stühmer
1Max-Planck-Institut für experimentelle Medizin, Göttingen, Germany.
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.
Related Concept Videos
tRNA Activation
ATP Synthase: Mechanism
ATP Synthase: Structure
ATP Driven Pumps II: P-type Pumps
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
tRNA Activation

