Part of an ABC transporter that catalyzes ATP-dependent electrogenic sodium extrusion. ATP + H2O + Na(+)(in) = ADP + H(+) + Na(+)(out) + phosphate The complex is composed of NatA and NatB. Induced by ethanol and the protonophore carbonylcyanide p-chlorophenylhydrazone (CCCP) and, more modestly, by sodium and potassium. Positively regulated by the two-component regulatory system NatK/NatR.