KcsA potassium channel

KcsA is a potassium ion (K⁺) channel derived from the bacterium *Streptomyces lividans*. It is one of the first potassium channels to be structurally characterized, providing significant insights into the mechanism of ion selectivity and channel function in biological systems. KcsA is a homotetrameric protein, meaning it is composed of four identical subunits that together form a central pore through which potassium ions can pass.