細菌の祖先型イオンチャネルから探る，普遍的なカルシウム選択機構

抄録

Voltage-dependent Ca²⁺ channels (Cavs) are indispensable for coupling action potentials with Ca²⁺ signaling. We report the first identification of a native prokaryotic Cav, CavMr, whose selectivity filter contains a smaller number of negatively charged residues than that of artificial prokaryotic Cavs. A relative mutant whose selectivity filter was replaced with that of CavMr exhibits high Ca²⁺ selectivity. The glycine residue of the CavMr selectivity filter is a determinant for Ca²⁺ selectivity. This glycine residue is well conserved among subdomains I and III of eukaryotic Cavs, which provide new insight into Ca²⁺ selectivity mechanism conserved from prokaryotes to eukaryotes.