Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
J Phys Chem Lett. 2022 Oct 13;13(40):9539-9543. doi: 10.1021/acs.jpclett.2c02334. Epub 2022 Oct 6.
Microbial and animal rhodopsins possess retinal chromophores which capture light and normally photoisomerize from all- to 13- and from 11 to all--retinal, respectively. Here, we show that a near-infrared light-absorbing enzymerhodopsin from (OmNeoR) contains the all- form in the dark but isomerizes into the 7- form upon illumination. The photoproduct (λ = 372 nm; P) possesses a deprotonated Schiff base, and the system exhibits a bistable nature. The photochemistry of OmNeoR was arrested at <270 K, indicating the presence of a potential barrier in the excited state. Formation of P is accompanied by protonation changes of protonated carboxylic acids and peptide backbone changes of an α-helix. Photoisomerization from the all- to 7- retinal conformation rarely occurs in any solvent and protein environments; thus, the present study reports on a novel photochemistry mediated by a microbial rhodopsin, leading from the all- to 7- form selectively.
微生物和动物视蛋白具有视黄醛发色团，可捕获光线，并分别将全- 13- 和 11- 异构化为全- 视网膜。在这里，我们表明，一种来自（OmNeoR）的近红外光吸收酶视蛋白含有全-形式在黑暗中，但在光照下异构化为 7-形式。光产物（λ = 372nm；P）具有去质子化的 Schiff 碱，并且该系统表现出双稳态性质。OmNeoR 的光化学反应在 <270 K 时被阻止，表明在激发态中存在潜在的势垒。P 的形成伴随着质子化羧酸的质子化变化和α-螺旋的肽骨架变化。全- 视网膜构象向 7-视网膜构象的光异构化很少在任何溶剂和蛋白质环境中发生；因此，本研究报告了一种由微生物视蛋白介导的新型光化学，可选择性地从全- 形式向 7- 形式转变。
