Voltage-gated sodium channel NaChBac (NaChBac)

NaChBac (Sodium Channel of Bacillus halodurans) is a prokaryotic voltage-gated sodium channel that serves as a foundational structural and functional model for eukaryotic voltage-gated sodium (Nav) and calcium (Cav) channels [2, 3]. Identified in the alkaliphilic bacterium Bacillus halodurans, it is a homotetramer composed of four identical subunits, each containing six transmembrane segments, which is a simpler architecture compared to the four-domain pseudo-tetrameric structure of human Nav channels [4, 10]. NaChBac demonstrates voltage-dependent activation and high selectivity for sodium ions, though its activation and inactivation kinetics are approximately 10 to 100 times slower than its mammalian counterparts [4, 9]. It is extensively utilized in pharmacological research to investigate the molecular basis of ion selectivity and the binding sites of drugs such as local anesthetics, antiarrhythmics, and calcium channel blockers [5, 7, 15]. Although it is not a direct therapeutic target for human diseases, it is a vital surrogate for studying channelopathies like epilepsy and cardiac arrhythmias [11, 15]. Furthermore, it serves as a tool in optogenetics and chemogenetics for modulating membrane potential in heterologous systems like neurons [12]. The channel's sensitivity to various toxins and small molecules makes it an ideal platform for high-throughput screening and structural biology studies [13, 15].

Other names

Sodium channel of Bacillus haloduransBacterial voltage-gated sodium channelNavBhSodium channel protein NaChBac

Inhibition of sodium ion conductance through pore blockade, stabilization of the inactivated state, or impedance of voltage-sensor activation [1, 5, 13].