PUBLICATION

Structural insights into the nucleotide base specificity of P2X receptors

Authors
Kasuya, G., Fujiwara, Y., Tsukamoto, H., Morinaga, S., Ryu, S., Touhara, K., Ishitani, R., Furutani, Y., Hattori, M., Nureki, O.
ID
ZDB-PUB-170324-7
Date
2017
Source
Scientific Reports   7: 45208 (Journal)
Registered Authors
Keywords
Biophysics, X-ray crystallography
MeSH Terms
  • Binding Sites
  • Cytidine Triphosphate/chemistry
  • Cytidine Triphosphate/metabolism*
  • Xenopus laevis
  • Zebrafish
  • Zebrafish Proteins/chemistry*
  • Zebrafish Proteins/metabolism
  • Protein Binding
  • Animals
  • Receptors, Purinergic P2X/chemistry*
  • Receptors, Purinergic P2X/metabolism
  • Molecular Docking Simulation
PubMed
28332633 Full text @ Sci. Rep.
Abstract
P2X receptors are trimeric ATP-gated cation channels involved in diverse physiological processes, ranging from muscle contraction to nociception. Despite the recent structure determination of the ATP-bound P2X receptors, the molecular mechanism of the nucleotide base specificity has remained elusive. Here, we present the crystal structure of zebrafish P2X4 in complex with a weak affinity agonist, CTP, together with structure-based electrophysiological and spectroscopic analyses. The CTP-bound structure revealed a hydrogen bond, between the cytosine base and the side chain of the basic residue in the agonist binding site, which mediates the weak but significant affinity for CTP. The cytosine base is further recognized by two main chain atoms, as in the ATP-bound structure, but their bond lengths seem to be extended in the CTP-bound structure, also possibly contributing to the weaker affinity for CTP over ATP. This work provides the structural insights for the nucleotide base specificity of P2X receptors.
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