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91.
Tatsuo Iwasa Fumio Tokunaga Thomas G. Ebrey Tru Yoshizawa 《Photochemistry and photobiology》1981,33(4):547-557
Abstract— The photoreaction of the artificial pigment synthesized from bacterioopsin and rrans-3,4-dehydro-retinal, [3,4-dehydro]bacteriorhodopsin ([3,4-deH]bRt ) was investigated with low temperature spectrophotometry.
The amount of batho-product formed from the light-adapted pigment of [3,4-deH]bR (designated as batho-[3,4-deH]bRt ) by irradiation at 77 K was much less than that from trans -bacteriorhodopsin (bRt ) and depends on temperature at irradiation of the sample. The kinetics of photoconversion of [3,4-deH]bRt to batho-[3,4-deH]bRt and that of its reversion were measured at several temperatures with a so-called "double Dewar system". The results showed that the photosensitivity of [3,4-deH]bRt was temperature dependent. When batho-[3,4-deH]bRt was warmed above 143 K, it was converted to lumi-[3,4-deH]bRt . Lumi-[3,4-deH]bRt was also produced by irradiation of [3,4-deH]bRt at 143 or 163 K. The maximum in the difference spectrum between lumi-[3,4-deH]bRt and [3,4-deH]bRt was located at about 540 nm. The irradiation of [3,4-deH]bRt at 183 K produced an intermediate analogous to meta-bRt , but under similar conditions bRt does not produce meta-bRt . These results indicate that intermediates of [3,4-deH]bRt are less stable than those of bRt .
The differences between bacteriorhodopsin and [3,4-dehydro]bacteriorhodopsin were discussed and compared with the differences between rhodopsin and [3,4-dehydro]rhodopsin. 相似文献
The amount of batho-product formed from the light-adapted pigment of [3,4-deH]bR (designated as batho-[3,4-deH]bR
The differences between bacteriorhodopsin and [3,4-dehydro]bacteriorhodopsin were discussed and compared with the differences between rhodopsin and [3,4-dehydro]rhodopsin. 相似文献
92.
93.
Manabu Iwasa 《Journal of multivariate analysis》1996,59(2):249-271
A variety of convolution inequalities have been obtained since Anderson's theorem. ?In this paper, we extend a convolution theorem forG-monotone functions by weakening the symmetry condition ofG-monotone functions. Our inequalities are described in terms of several orderings obtained from a cone. It is noteworthy that the orderings detect differences in directions. A special case of the orderings induces a majorization-like relation on spheres. Applying our inequality, Bartholomew's conjectures, which concern directions yielding the maximum power and the minimum power of likelihood ratio tests for order-restricted alternatives, are partly settled. 相似文献
94.
Shimotani H Ito T Iwasa Y Taninaka A Shinohara H Nishibori E Takata M Sakata M 《Journal of the American Chemical Society》2004,126(1):364-369
The configuration of La ions of La(2)@C(80) in the [80]fullerene cage was investigated by use of quantum chemical calculations. We found that the D(3)(d)() configuration is the global minimum in total energy, being more stable by 1.9 kcal/mol than the D(2)(h)() configuration, which has been considered to be the most stable. The potential energy surface calculation clarified that La ions travel between 10 equivalent D(3)(d)() positions through D(2)(h)() positions and consequently form pentagonal dodecahedral trajectory, which is in good agreement with the previous synchrotron radiation structural study. The experimental and theoretical investigation of the Raman spectrum revealed that the symmetry of molecular vibration is dramatically reduced simply by encapsulation of two La ions, and resulting vibrational modes were successfully assigned. The Raman peak at 163 cm(-)(1) was interpreted as the in-phase synchronously coupled mode of the [80]fullerene cage elongation and the La-La stretching, rather than a conventional and naive assignment as a metal-to-cage vibration mode. 相似文献
95.
Miyoko Kamigauchi Narumi Kanbara Makiko Sugiura Kinuko Iwasa Hirofumi Ohishi Toshimasa Ishida 《Helvetica chimica acta》2004,87(1):264-271
To understand the increased solubility and decreased bitter taste of berberine, a clinically important isoquinoline alkaloid, in the presence of cyclodextrins, the interaction with γ‐cyclodextrin (γ‐CD) in aqueous solution was studied by a combination of 1H‐NMR analyses and molecular‐dynamics calculations. The proposed complexation mode of berberine by γ‐CD could explain the increased solubility in water. No difference in germicidal activity between berberine alone and its inclusion complex with γ‐ or β‐CD was observed, which is important to further develop the pharmacological application of berberine. 相似文献
96.
From Corydalis incisa (+)-corynoline (2) was isolated together with (±)-corynoline (2'), which has been reported to be the major alkaloid. Optical resolution of 2' was achieved by resolving the corresponding diastereomeric esters with (-)-menthoxyacetic acid. The quaternary hydroxide of (+)-corynoline-O-acetate (3) was subjected to Emde degradation to afford the hydromethine base (5), the methiodide of which was converted by further Emde degradation into the optically active nitrogenfree product (6). This product was identical with the nitrogen-free product resulting from Emde degradation of (+)-14-epicorynoline (1), whose absolute configuration has been determined by means of an X-ray analysis. This result shows the absolute configuration of (+)-corynoline (2) to be 11S, 13R and 14R. 相似文献
97.
Chiral 4,5-bis(2-oxazolinyl)-(2,7-di-tert-butyl-9,9-dimethyl)-9H-xanthenes (xabox) were synthesized and the chiral environments were evaluated in catalytic asymmetric 1,3-dipolar cycloaddition reactions of nitrones resulting in good to excellent enantioselectivities. 1,3-Dipolar cycloaddition reactions of nitrones with 3-crotonoyl-2-oxazolidinone in the presence of a bis(2-oxazolinyl)xanthene (4c; xabox-Bn) and Mn(II) or Mg(II) complex as a chiral Lewis acid catalyst proceeded smoothly to give the corresponding cycloadducts ranging from 96:4 to >99:1 of endo:exo ratio and ranging from 91% to 98% ee for the endo adduct. 相似文献
98.
99.
Abstract— An action spectrum for photoreactivation was measured with Halobacterium halobium R1 m1 to prove a role of carotenoid pigments in photoreactivation of the bacteria. The action spectrum obtained showed a main peak at 435 nm and a minor peak at about 325 nm. The action spectrum was similar to that of Streptomyces pigment (Eker et al. , 1981) suggesting that the chromophore of the photoreactivating enzyme in Halobacterium halobium is 8-OH-5-deazaflavin. The minor peak may be due to photochemical cleavage of a pyrimidine6–4 hetero adduct. The result indicates that carotenoid pigments do not play a positive role in enhancing photoreactivation. This was confirmed also by comparing the efficiency of photoreactivation at 465 nm among three strains of Halobacterium halobium having different carotenoid pigments; R1 m1 . R1 and W5002–1. 相似文献
100.
Abstract— The photoreaction of the acidified form of bacteriorhodopsin and its 9-cis derivative was studied by low temperature spectroscopy.
A short exposure of the acidified form of bacteriorhodopsin, which was prepared by adding 2 m M HC1 to purple membrane suspension in 67% glycerol at 0°C, to red light at – 72°C resulted in the blue-shift of the spectrum. The feature of the shift was very similar to that accompanied by the formation of stable 9- cis acidified form of bacteriorhodopsin at 0°C, but only 13- cis - and all- trans -retinals were found in the extract from this product. No blue-shifted product was found on irradiation at – 190°C.
Irradiation of the 9- cis form of acidified bacteriorhodopsin at -72°C with blue light caused the isomerization of its 9- cis -retinylidene chromophore to 13- cis and all- trans forms without a significant spectral change. It became greater only after the sample was warmed above – 24°C. These results indicate the presence of the light-induced product which has trans configuration on the 9-10 double bond and exhibits the 9- cis type spectrum. 相似文献
A short exposure of the acidified form of bacteriorhodopsin, which was prepared by adding 2 m M HC1 to purple membrane suspension in 67% glycerol at 0°C, to red light at – 72°C resulted in the blue-shift of the spectrum. The feature of the shift was very similar to that accompanied by the formation of stable 9- cis acidified form of bacteriorhodopsin at 0°C, but only 13- cis - and all- trans -retinals were found in the extract from this product. No blue-shifted product was found on irradiation at – 190°C.
Irradiation of the 9- cis form of acidified bacteriorhodopsin at -72°C with blue light caused the isomerization of its 9- cis -retinylidene chromophore to 13- cis and all- trans forms without a significant spectral change. It became greater only after the sample was warmed above – 24°C. These results indicate the presence of the light-induced product which has trans configuration on the 9-10 double bond and exhibits the 9- cis type spectrum. 相似文献