[WS5] 高速分子動画：タンパク質の構造機能相関研究の最先端

[WS5-01] 海洋微生物塩化物イオンポンプロドプシンNM-R3 の機構解明

大木 規央¹, ユン ジーヘ², 柴山 修哉³, 李 ウエンテ², ^○朴 三用¹ (1.横浜市大・生命医科学, 2.延世大学校理学部, 3.自治医大)

A novel microbial rhodopsin, NM-R3, from the marine flavobacterium Nonlabens marinus, was recently shown to drive chloride ion uptake, extending our understanding of the diversity of mechanisms for biological energy conversion. To clarify the mechanism underlying its function, we characterized the crystal structures of NM-R3 in both the dark state and early intermediate photo-excited states produced by laser pulses of different intensities and temperatures. The displacement of chloride ions at different locations in the model reflected the detailed anion-conduction pathway and key residues were identified by mutation assays and spectroscopy. Comparisons with other proteins, including a closely related outward sodium ion pump, revealed key motifs and provided structural insights into light-driven ion transport across membranes by the NQ subfamily of rhodopsins.