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Updated: Sep 30, 2026

Proteomics to Identify Proteins Interacting with P2X2 Ligand-Gated Cation Channels
Published on: May 18, 2009
Size of side-chain at channel pore mouth affects Ca(2+) block of P2X(2) receptor
Ken Nakazawa1, Hideaki Sawa, Hiloe Ojima
1Cellular and Molecular Pharmacology Section, National Institute of Health Sciences, 1-18-1 Kamiyoga, Segataya, Tokyo, 158-8501, Japan. nakazawa@nihs.go.jp
Abstract:
Effects of amino acid replacement at the channel pore mouth of P2X(2) receptor/channel on multivalent cation channel block were investigated. When Asn(333) was replaced with various amino acid residues with neutral side chains (Gly, Ala, Val, Leu and Ile), the block by Ca(2+) was attenuated according to the sizes of the side chains. The block by La(3+) was also greatest with the Gly-substituted mutant, but this preference was not found for the block by other multivalent cations tested. The side chain at the channel pore mouth may interfere with the access of Ca(2+) block by steric hindrance.
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