Reisomerization of retinal represents a molecular switch mediating Na⁺ uptake and release by a bacterial sodium-pumping rhodopsin.

ABSTRACT: Sodium-pumping rhodopsins (NaRs) are membrane transporters that utilize light energy to pump Na⁺ across the cellular membrane. Within the NaRs, the retinal Schiff base chromophore absorbs light, and a photochemically induced transient state, referred to as the "O intermediate", performs both the uptake and release of Na⁺. However, the structure of the O intermediate remains unclear. Here, we used time-resolved cryo-Raman spectroscopy under preresonance conditions to study the structure of the retinal chromophore in the O intermediate of an NaR from the bacterium Indibacter alkaliphilus. We observed two O intermediates, termed O1 and O2, having distinct chromophore structures. We show O1 displays a distorted 13-cis chromophore, while O2 contains a distorted all-trans s

SUBMITTER: Fujisawa T 

PROVIDER: S-EPMC9483557 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature