The University of Osaka · 신경과학
미즈타니 요시사부 교수 연구실은 초속 및 피코초 스케일의 분자 동역학을 시간해상도 높은 라만 분광법을 통해 연구하는 데 전문성을 가진다. 주로 헴 기반 단백질(예: 미오글로빈, 페오토크로마틴)과 페오토크로마틴의 광분해 이후의 구조적 변화와 진동 에너지 소산 메커니즘을 중심으로 연구한다. 특히 시간해상도 레조넌스 라만 분광법을 활용해 광활성 상태에서의 전자 상태 변화, 금속-리간드 결합의 동적 거동, 그리고 샤프의 기저의 탈질소화 과정을 고해상도로 분석한다. 이는 단백질 내 광화학 반응의 기초 메커니즘을 밝히는 데 기여한다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
The formation of vibrationally excited heme upon photodissociation of carbonmonoxy myoglobin and its subsequent vibrational energy relaxation was monitored by picosecond anti-Stokes resonance Raman spectroscopy. The anti-Stokes intensity of the nu4 band showed immediate generation of vibrationally excited hemes and biphasic decay of the excited populations. The best fit to double exponentials gave time constants of 1.9 +/- 0.6 and 16 +/- 9 picoseconds for vibrational population decay and 3.0 +/-
Studies on the structural relaxation of myoglobin following CO photolysis revealed that the structural change of heme itself caused by the cleavage of the Fe−CO bond is completed within the instrumental response time (∼2 ps) of the time-resolved resonance Raman apparatus used. In contrast, changes in the intensity and frequency of the iron-histidine stretching [ν(Fe−His)] mode were found to occur in the picosecond regime. The ν(Fe−His) band is absent for the CO-bound form, and its appearance upo
Recent experimental work carried out in this laboratory on the ultrafast dynamics of myoglobin (Mb) is summarized with a stress on structural and vibrational energy relaxation. Studies on the structural relaxation of Mb following CO photolysis revealed that the structural change of heme itself, caused by CO photodissociation, is completed within the instrumental response time of the time-resolved resonance Raman apparatus used (approximately 2 ps). In contrast, changes in the intensity and frequ
The formation of a vibrationally excited photoproduct of nickel octaethylporphyrin (NiOEP) upon (π, π*) excitation and its subsequent vibrational energy relaxation were monitored by picosecond time-resolved resonance Raman spectroscopy. Stokes Raman bands due to the photoproduct instantaneously appeared upon the photoexcitation. Their intensities decayed with a time constant of ∼300 ps, which indicates electronic relaxation from the (d, d) excited state (B1g) to the ground state (A1g), being con
Resonance Raman (RR) scattering from type A large phytochrome of pea was measured at cryogenic as well as ambient temperatures to determine an intermediate in which deprotonation of the chromophore takes place. The RR bands of the red-absorbing (Pr) and far-red-absorbing forms (Pfr) of large pea phytochromes at ambient temperatures are almost the same in their frequencies as those of the intact form reported previously (Mizutani et al., 1991). The RR spectrum of large phytochrome excited at 364
We conducted a comprehensive time-resolved resonance Raman spectroscopy study of the structures of the retinal chromophore during the photocycle of the sodium-ion pump Krokinobacter rhodopsin 2 (KR2). We succeeded in determining the structure of the chromophore in the unphotolyzed state and in the K, L, M, and O intermediates, by overcoming the problem that only a small fraction of the M intermediate is accumulated in the KR2 photocycle. The Schiff base in the retinal chromophore forms a strong
Heliorhodopsins (HeRs) are a new category of retinal-bound proteins recently discovered through functional metagenomics analysis that exhibit obvious differences from type-1 microbial rhodopsins. We conducted the first detailed structural characterization of the retinal chromophore in HeRs using resonance Raman spectroscopy. The observed spectra clearly show that the Schiff base of the chromophore is protonated and forms a strong hydrogen bond to a species other than a water molecule, highly lik
Resonance Raman (RR) scattering from intact pea phytochrome was observed in resonance with the blue band at ambient temperature. The relative populations of the red-light-absorbing form (Pr) and far-red-light-absorbing form (Pfr) under laser illumination were estimated from the absorption spectra. The most prominent RR band of Pr obtained by 364-nm excitation under 740-nm pumping exhibited a frequency shift between H2O and D2O solutions, but that of Pfr obtained by 407-nm excitation under 633-nm
Abstract Protein dynamics play a fundamental role in allosteric regulation, which is vital to the function of many proteins. In many proteins, rather than a direct interaction, mutual modulation of properties such as ligand affinity at spatially separated sites is achieved through a conformational change. Conformational changes of proteins are thermally activated processes that involve intramolecular and intermolecular energy exchanges. In this account, I review the work of my team on the develo
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of urea on hydrophobic interaction: Raman difference spectroscopy on the carbon-hydrogen stretching vibration of acetone and the carbon-nitrogen stretching vibration of ureaYasuhisa Mizutani, Keiji Kamogawa, and Koichiro NakanishiCite this: J. Phys. Chem. 1989, 93, 15, 5650–5654Publication Date (Print):July 1, 1989Publication History Published online1 May 2002Published inissue 1 July 1989https://pubs.acs.org/doi/10.1021/j100352a005https://doi.or
We revealed the chloride ion pumping mechanism in halorhodopsin from Natronobacterium pharaonis ( pHR) by exploring sequential structural changes in the retinal chromophore during its photocycle using time-resolved resonance Raman (RR) spectroscopy on the nanosecond to millisecond time scales. A series of RR spectra of the retinal chromophore in the unphotolyzed state and of the three intermediates of pHR were obtained. Using singular value decomposition analysis of the C═C and C-C stretch bands
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolution structures and phase separation in fluoro alcohol/water mixtures: a study with Raman difference and carbon-13 NMR spectroscopyYasuhisa Mizutani, Keiji Kamogawa, Teizo Kitagawa, Akio Shimizu, Yoshihiro Taniguchi, and Koichiro NakanishiCite this: J. Phys. Chem. 1991, 95, 4, 1790–1794Publication Date (Print):February 1, 1991Publication History Published online1 May 2002Published inissue 1 February 1991https://pubs.acs.org/doi/10.1021/j100157a055h
Abstract Recent experimental work on vibrational energy relaxation of metalloporphyrins in a condensed phase carried out in this laboratory is summarized. The formation of a vibrationally excited photoproduct of metalloporphyrins upon (π, π*) excitation and its subsequent vibrational energy relaxation were monitored by picosecond time-resolved resonance Raman spectroscopy. Results related to intramolecular relaxation of octaethylporphyrinato nickel (NiOEP) are described. Stokes Raman bands due t
