The Role of the NDQ Motif in Sodium‐Pumping Rhodopsins

Sodium-pumping rhodopsins (NaRs) are light-driven outward Na(+) pumps. NaRs have a conserved Asn, Asp, and Gln motif (NDQ) in the third transmembrane helix (helix C). The NDQ motif is thus expected to play a crucial role in the operation of the Na(+) pump. Herein, we studied the photocycles of the NDQ-motif mutants of Krokinobacter rhodopsin 2 (KR2), the first discovered NaR, by flash photolysis, to obtain insight into the mechanism of Na(+)...