Details

Autor(en) / Beteiligte

• Jakdetchai, Orawan
• Eberhardt, Peter
• Asido, Marvin
• Kaur, Jagdeep
• Kriebel, Clara Nassrin
• Mao, Jiafei
• Leeder, Alexander J
• Brown, Lynda J
• Brown, Richard C D
• Becker-Baldus, Johanna
• Bamann, Christian
• Wachtveitl, Josef
• Glaubitz, Clemens

Titel

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

Ist Teil von

• Science advances, 2021-03, Vol.7 (11)

Ort / Verlag

United States: American Association for the Advancement of Science

Erscheinungsjahr

2021

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• The functional mechanism of the light-driven sodium pump 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- 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, retinal carbon and Schiff base nitrogen chemical shifts differ from those observed in the KR2 dark state all- conformation, indicating a perturbation through the nearby bound sodium ion. Our findings are supplemented by optical and infrared spectroscopy and are discussed in the context of known three-dimensional structures.