Structural insights into the nucleotide base specificity of P2X receptors.
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.
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan.
Go
G
Kasuya
Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan.
Yuichiro
Y
Fujiwara
Institute for Molecular Science, 38 Nishigo-Naka, Myodaiji, Okazaki, 444-8585, Japan.
Hisao
H
Tsukamoto
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.|ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
Satoshi
S
Morinaga
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.|ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
Satoshi
S
Ryu
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.|ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
Kazushige
K
Touhara
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan.
Ryuichiro
R
Ishitani
Institute for Molecular Science, 38 Nishigo-Naka, Myodaiji, Okazaki, 444-8585, Japan.
Yuji
Y
Furutani
State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai, 200438, China.
Motoyuki
M
Hattori
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan.
Osamu
O
Nureki
D000818:Animals; D001665:Binding Sites; D003570:Cytidine Triphosphate / Q000737:chemistry / Q000378:metabolism*; D062105:Molecular Docking Simulation; D011485:Protein Binding; D058469:Receptors, Purinergic P2X / Q000737:chemistry* / Q000378:metabolism; D014982:Xenopus laevis; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000737:chemistry* / Q000378:metabolism
D058469:Receptors, Purinergic P2X; D029961:Zebrafish Proteins; D003570:Cytidine Triphosphate