Probing the photointermediates of light-driven sodium ion pump KR2 by DNP-enhanced solid-state NMR.

ABSTRACT: The functional mechanism of the light-driven sodium pump Krokinobacter eikastus rhodopsin 2 (KR2) raises fundamental questions since the transfer of cations must differ from the better-known principles of rhodopsin-based proton pumps. Addressing these questions must involve a better understanding of its photointermediates. Here, dynamic nuclear polarization-enhanced solid-state nuclear magnetic resonance spectroscopy on cryo-trapped photointermediates shows that the K-state with 13-cis retinal directly interconverts into the subsequent L-state with distinct retinal carbon chemical shift differences and an increased out-of-plane twist around the C14-C15 bond. The retinal converts back into an all-trans conformation in the O-intermediate, which is the key state for sodium transport. However,

SUBMITTER: Jakdetchai O 

PROVIDER: S-EPMC7954446 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature