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31 巻, 3 号
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「光受容蛋白質のピコ秒・フェムト秒分子ダイナミクス」特集号
解説小特集
レーザー解説
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“蛋白質—この複雑にして神秘的なるもの”山崎 巌原稿種別: その他
専門分野: その他
2003 年 31 巻 3 号 p. 176
発行日: 2003年
公開日: 2006/02/03
ジャーナル フリーPDF形式でダウンロード (117K) -
又賀 のぼる, コスロービアン ハイク, 谷口 誠治原稿種別: その他
専門分野: その他
2003 年 31 巻 3 号 p. 177-183
発行日: 2003年
公開日: 2006/02/03
ジャーナル フリーWe have studied primary processes of ultrafast photoisomerization reactions of photoactive yellow protein (PYP) and visual rhodopsin (Rh) as well as ultrafast photoinduced electron transfer reactions of flavoproteins (FP) by means of the fs fluorescence up-conversion method. On the basis of these studies, we have examined the effects of the protein nanospace (PNS), where the chromophore is held, on the dynamics and mechanisms of the ultrafast and highly efficient photoinduced reactions of these proteins. In this article, we discuss mainly results of our comparative fluorescence dynamics studies on wild type (w. -t.) PYP, it’s site-directed mutants, analogues with replaced chromophore and FP, including the coherent vibrations in the ultrafast fluorescence decays of w. -t. PYP and mutants in the course of the photoisomerization, ultrafast dynamic Stokes shift of fluorescence of PYP analogues, and ultrafast electron transfer of FP.抄録全体を表示PDF形式でダウンロード (882K) -
神取 秀樹原稿種別: その他
専門分野: その他
2003 年 31 巻 3 号 p. 184-189
発行日: 2003年
公開日: 2006/02/03
ジャーナル フリーThis article reviews the primary reaction processes in rhodopsin, a light-sensor protein in our vision. Rhodopsin has an 11-cis retinal as the chromophore, which binds covalently with a lysine residue through a protonated Schiff base linkage. Picosecond time-resolved spectroscopy of 11-cis locked rhodopsin analogs revealed that the cis-trans isomerization of the chromophore is the primary reaction in rhodopsin. Then, generation of femtosecond laser pulses in the 1990s made it possible to follow the process of isomerization in real time. Formation of photorhodopsin within 200 fs was observed by a transient absorption (pump-probe) experiment, which also revealed that the photoisomerization in rhodopsin is a vibrationally coherent process. Femtosecond fluorescence spectroscopy directly captured excited-state dynamics of rhodopsin, so that both coherent reaction process and unreacted excited state were observed. Faster photoreaction of the chromophore in rhodopsin than that in solution implies that the protein environment facilitates the efficient isomerization process.抄録全体を表示PDF形式でダウンロード (986K) -
中島 聡原稿種別: その他
専門分野: その他
2003 年 31 巻 3 号 p. 190-194
発行日: 2003年
公開日: 2006/02/03
ジャーナル フリーRecent revolutionary festinate development of the ultrafast laser technology enable us to take the snapshot of the molecular motion in real-time. These methods have been applied to the dynamics of the photoresponce for many proteins and have shown that the coherence of the vibrational modes of the proteins are sometimes strongly related to their functions. This article reviews such ultrafast photoresponce and their coherent modes of proteins including our recent results. In blue copper protein plastocyanin, which transport electron in photosystem, LMCT band can excite by the laser pulse and the back-electron transfer that takes approximately same pathway for physiological functions, can be probed. In this case, the coherent protein skeletal mode was induced by the reaction. These results shows that protein matrix modes have selectivity for the effective functions of the protein.抄録全体を表示PDF形式でダウンロード (903K) -
寺嶋 正秀原稿種別: その他
専門分野: その他
2003 年 31 巻 3 号 p. 195-201
発行日: 2003年
公開日: 2006/02/03
ジャーナル フリーThere are many proteins that use photon energy as driving force for biological functions. The excess energy which was not used for the function ultimately flows into the thermal mode to heat up the system. Not only the light sensitive proteins, but also many molecules that absorb light in condensed phase release all or a part of the photon energy to the matrix as the thermal energy. The energy dissipation processes of rather small organic molecules as well as a biological protein, myoglobin, are studied by monitoring the solvent temperature rise in picoseconds time range. The energy dissipation processes from these photoexcited molecules are described.抄録全体を表示PDF形式でダウンロード (1198K) -
熊崎 茂一原稿種別: その他
専門分野: その他
2003 年 31 巻 3 号 p. 202-206
発行日: 2003年
公開日: 2006/02/03
ジャーナル フリーA brief review is given on how ultrafast laser spectroscopy has been recently applied to the research of photosynthetic reaction center, which achieves the most essential energy conversion from light to chemical (physiological) energy. Photosystem I reaction center (PSIRC) is one of the several types of photosynthetic reaction center, and it is working in plants and some photosynthetic bacteria. Light-illuminated PSIRC generates the highest reducing capability among all biological systems, which is necessary for the reduction of carbon dioxide, the most controversial greenhouse effect gas. The understanding on PSIRC has been relatively delayed due to its stoichiometric and spectroscopic complexity. Thanks to the advance of ultrafast laser spectroscopy and the finely determined crystal structure in 2001, very detailed picture is being rapidly constructed on the mechanism of the electronic excitation transfer and the primary charge separation processes among the constituent chlorophylls in PSIRC.抄録全体を表示PDF形式でダウンロード (687K) -
秋本 誠志, 山崎 巌, 三室 守原稿種別: その他
専門分野: その他
2003 年 31 巻 3 号 p. 207-211
発行日: 2003年
公開日: 2006/02/03
ジャーナル フリーExcited state dynamics of carotenoids were investigated to access relationship among molecular structures, dynamics, and energy transfer to chlorophylls in photosynthetic pigment protein complexes. The relaxation kinetics are strongly affected by conjugation systems, such as conjugation length and an additional conjugation with a keto-carbonyl group. Energy transfer pathways also depend on the conjugation systems; the energy transfer to chlorophyll occurred via the S2 state of carotenoids for polyene-type carotenoids, whereas the S2 transfer was not recognized for the carotenoids which have a keto-carbonyl group in their conjugations.抄録全体を表示PDF形式でダウンロード (683K)
レーザーオリジナル
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－フェムト秒,ピコ秒領域時間分解蛍光スペクトル法による解析－三室 守, 秋本 誠志, 山崎 巌原稿種別: その他
専門分野: その他
2003 年 31 巻 3 号 p. 212-218
発行日: 2003年
公開日: 2006/02/03
ジャーナル フリーExcitation energy transfer pathways and mechanisms in the antenna systems of oxygenic photosynthetic organisms were discussed from the viewpoint of methodology of analyses. Time-resolved fluorescence spectroscopy in the picosecond and femtosecond time range and its analytical method were applied to intact cells of cyanobacteria and one species of cryptophyceae, furthermore, a unique phycobiliproteins of cyanobacteria, APC-B. Finally, the most abundant antenna complex of higher plants, that is, light-harvesting complex II (LHC II) was described in detail on the molecular arrangement of chlorophyll molecules and energy transfer pathways among those molecules.抄録全体を表示PDF形式でダウンロード (1076K)
一般論文
レーザーオリジナル
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内藤 康秀, 佐々木 理江, 部谷 学, 粟津 邦男原稿種別: その他
専門分野: その他
2003 年 31 巻 3 号 p. 219-224
発行日: 2003年
公開日: 2006/02/03
ジャーナル フリーA use of a free-electron laser (FEL) as the source of selective vibrational excitation was examined for infrared matrix-assisted laser desorption/ionization time of flight mass spectrometry (IR-MALDI-TOFMS). A polycrystalline mixture of fumaric acid/potassium chloride was exposed to FEL macropulses (15 μs). To make comparison, a pulse TEA-CO2 laser was also employed for the light source of IR-MALDI-TOFMS. In the present study, both the FEL and CO2 lasers were tuned at 10.2 μm. Preliminary results and novel findings are reported. The ability of ionization in the mid-infrared wavelength was evidenced by the mass spectrometric detection of fumaric acid ions. Contrastive absence and presence of low m/z peaks in the TOFMS spectra imply that a softer situation of desorption-ionization was achieved by exposure to the FEL than that to the CO2 laser. A novel ionization process via absorption of a single micropulse was suggested to be possible.抄録全体を表示PDF形式でダウンロード (878K) -
松永 隆, 佐藤 三郎, 山部 長兵衛原稿種別: その他
専門分野: その他
2003 年 31 巻 3 号 p. 225-230
発行日: 2003年
公開日: 2006/02/03
ジャーナル フリーWe did experiments and consideration of the relation between the pulse width of the pulsed-power supply output and KrF excimer laser efficiency. The breakdown voltage rises when the pulse width is decreased and as a result, the laser oscillation efficiency is improved. On the other hand, the efficiency of the pulsed-power supply with the magnetic pulse compression circuit decreases because of an increase of the core volume and the compression stage number to achieve the short pulse output. To evaluate total efficiency of KrF excimer laser, we considered both the pulsed-power supply efficiency and the laser oscillation efficiency. As a result, we have arrived at the conclusion that there is a limit to improve the total efficiency by short pulse of the pulsed-power supply output. The pulse width limit is 70 to 100 nsec in our KrF excimer laser.抄録全体を表示PDF形式でダウンロード (573K) -
川人 洋介, 船見 浩司, 岡田 俊治, 片山 聖二原稿種別: その他
専門分野: その他
2003 年 31 巻 3 号 p. 231-235
発行日: 2003年
公開日: 2006/02/03
ジャーナル フリーA new procedure of in-process monitoring and adaptive control is developed for micro-spot welding of 0.1-mm-thick copper sheets with combined beams of an AO Q-switched second harmonic YAG laser and a pulsed fundamental YAG laser. The objective of this method is to consistently produce fully penetrated welds stably. The pulse width of the fundamental YAG laser is controlled at 0.15-ms intervals during laser irradiation according to the neural network judgment of reflected beam and heat radiation from each processing area. This is accomplished by using a database of these values corresponding to the diameters of spot-weld fusion zones on the back surface. Through investigation of 200 samples, incomplete melting was detected in 7 samples under the laser irradiation conditions used conventionally. On the other hand, fully penetrated spot welds were stably produced in 200 samples subjected to the proposed in-process monitoring and adaptive control.抄録全体を表示PDF形式でダウンロード (1102K)
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