Channel gating in response to extracellular ATP is a fundamental process for the physiological functions of P2X receptors. Here we identify coordinated allosteric changes in the left flipper (LF) and dorsal fin (DF) domains that couple ATP-binding to channel gating. Engineered disulphide crosslinking or zinc bridges between the LF and DF domains that constrain their relative motions significantly influence channel gating of P2X4 receptors, confirming the essential role of these allosteric changes. ATP-binding-induced alterations in interdomain hydrophobic interactions among I208, L217, V291 and the aliphatic chain of K193 correlate well with these coordinated relative movements. Mutations on those four residues lead to impaired or fully abolished channel activations of P2X4 receptors. Our data reveal that ATP-binding-induced altered interdomain hydrophobic interactions and the concomitant coordinated motions of LF and DF domains are allosteric events essential for the channel gating of P2X4 receptors.
[1]Shanghai Jiao Tong Univ, Sch Med, Inst Med Sci, Shanghai 200025, Peoples R China.
[2]Shanghai Jiao Tong Univ, Sch Med, Dept Pharmacol, Shanghai 200025, Peoples R China.
[3]Lanzhou Univ, Key Lab Preclin Study New Drugs Gansu Prov, Sch Basic Med Sci, Lanzhou 730000, Peoples R China.
[4]Hunan Agr Univ, Coll Biosci & Biotechnol, Changsha 410128, Hunan, Peoples R China.
[5]Shanghai Univ Chinese Tradit Med, Putuo Dist Ctr Hosp, Shanghai 200062, Peoples R China.
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