근접장 마이크로파 현미경을 이용한 로돕신의 광학적 특성 연구

초록

We report the electro-optical properties of the sensory rhodopsin II using a near-field scanning microwave microscope(NSMM). Rhodopsin was known as a photoreceptor pigment with a retinal as a chromophore via a protonated Schiff base and consists of seven α-helical transmembrane segments. The sensory rhodopsin II, expressing E. coli UT5600 with endogenous retinal biosynthesis system and purified with Ni+2-NTA affinity chromatography in the presence of 0.02 % DM (Dodecyl Maltoside) from Natronomonas pharaonis. We measured the absorption spectra and the transients difference of sensory rhodopsin II from Natronomonas pharaonis using a UV/VIS spectrophotometer with Nd-Yag Laser (532 nm). The absorption spectra of NpSR II showed a typical rhodopsin spectrum with a left shoulder region and the photointermediates spectra of NpSR II- ground state (λmax=498 nm), NpSR II-M state (λmax=390 nm), and NpSR II-O state (λmax=550 nm) during the photocycle. The observed photocycle reaction was confirmed by measuring the microwave reflection coefficient S11 at an operating frequency of =3.93-3.95 GHz and compared with the results of a photocycle of NpSR II.

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