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排序方式: 共有70条查询结果,搜索用时 78 毫秒
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Habuchi S Cotlet M Gensch T Bednarz T Haber-Pohlmeier S Rozenski J Dirix G Michiels J Vanderleyden J Heberle J De Schryver FC Hofkens J 《Journal of the American Chemical Society》2005,127(25):8977-8984
Recently, it has been shown that the red fluorescent protein DsRed undergoes photoconversion on intense irradiation, but the mechanism of the conversion has not yet been elucidated. Upon irradiation with a nanosecond-pulsed laser at 532 nm, the chromophore of DsRed absorbing at 559 nm and emitting at 583 nm (R form) converts into a super red (SR) form absorbing at 574 nm and emitting at 595 nm. This conversion leads to a significant change in the fluorescence quantum yield from 0.7 to 0.01. Here we demonstrate that the photoconversion is the result of structural changes of the chromophore and one amino acid. Absorption, fluorescence, and vibrational spectroscopy as well as mass spectrometry suggest that a cis-to-trans isomerization of the chromophore and decarboxylation of a glutamate (E215) take place upon irradiation to form SR. At the same time, another photoproduct (B) with an absorption maximum at 386 nm appears upon irradiation. This species is assigned as a protonated form of the DsRed chromophore. It might be a mixture of several protonated DsRed forms as there is at least two ways of formation. Furthermore, the photoconversion of DsRed is proven to occur through a consecutive two-photon absorption process. Our results demonstrate the importance of the chromophore conformation in the ground state on the brightness of the protein as well as the importance of the photon flux to control/avoid the photoconversion process. 相似文献
24.
By means of the Cayley Trick the problem of enumerating all regular fine mixed subdivisions is reduced to enumerating all
regular triangulations. The set of all regular triangulations is well understood thanks to the bijection with the vertices
of the secondary polytope. However, since we are only interested in the configurations of mixed cells in a mixed subdivision,
we want to avoid dealing with other cells. We propose an operator derived from the bistellar flip for regular triangulations
to modify a mixed-cell configuration.
Received June 30, 1997, and in revised form December 1, 1997. 相似文献
25.
F. Michiels W. Vanhoolst P. Van Espen F. Adams 《Journal of the American Society for Mass Spectrometry》1990,1(1):37-52
The quantitative analytical characteristics of a camera-based detection system for secondary ion microscopy are studied in detail. Through multiple exposures, ion images with large dynamic ranges are obtained. The quantification of these images by the sensitivity factor method and the matrix ion species ratio method is described and evaluated by the analysis of steel and aluminum standard reference materials. 相似文献
26.
We investigate nonlinear oscillations in a fourth-order partialdifferential equation which models a suspension bridge. Previouswork establishes multiple periodic solutions when a parameterexceeds a certain eigenvalue. In this paper, we use Leray-Schauderdegree theory to prove that if the parameter is increased further,beyond a second eigenvalue, then additional solutions are created. 相似文献
27.
Single-molecule surface enhanced resonance Raman spectroscopy of the enhanced green fluorescent protein 总被引:1,自引:0,他引:1
Habuchi S Cotlet M Gronheid R Dirix G Michiels J Vanderleyden J De Schryver FC Hofkens J 《Journal of the American Chemical Society》2003,125(28):8446-8447
In the present contribution, we demonstrated that surface-enhanced resonance Raman scattering spectra from single green fluorescent proteins (GFPs) were obtained. The most important findings are the direct detection of the conversion between a deprotonated and a protonated form of the chromophore at the single-molecule level via the corresponding vibrational fingerprints, and the fact that the enhanced green fluorescent protein (EGFP) also shows a high surface enhanced resonance Raman scattering (SERRS) signal. Our findings show the potential of the technique to study structural dynamics of protein molecules at a single-molecule level. 相似文献
28.
The vertices of the secondary polytope of a point configuration correspond to its regular triangulations. The Cayley trick
links triangulations of one point configuration, called the Cayley polytope, to the fine mixed subdivisions of a tuple of
point configurations. In this paper we investigate the secondary polytope of this Cayley polytope. Its vertices correspond
to all regular mixed subdivisions of a tuple of point configurations. We demonstrate that it equals the Minkowski sum of polytopes,
which we call mixed secondary polytopes, whose vertices correspond to regular-cell configurations.
Received October 1, 1998, and in revised form July 23, 1999. 相似文献
29.
Wenmackers S Pop SD Roodenko K Vermeeren V Williams OA Daenen M Douhéret O D'Haen J Hardy A Van Bael MK Hinrichs K Cobet C vandeVen M Ameloot M Haenen K Michiels L Esser N Wagner P 《Langmuir : the ACS journal of surfaces and colloids》2008,24(14):7269-7277
Label-free detection of DNA molecules on chemically vapor-deposited diamond surfaces is achieved with spectroscopic ellipsometry in the infrared and vacuum ultraviolet range. This nondestructive method has the potential to yield information on the average orientation of single as well as double-stranded DNA molecules, without restricting the strand length to the persistence length. The orientational analysis based on electronic excitations in combination with information from layer thicknesses provides a deeper understanding of biological layers on diamond. The pi-pi* transition dipole moments, corresponding to a transition at 4.74 eV, originate from the individual bases. They are in a plane perpendicular to the DNA backbone with an associated n-pi* transition at 4.47 eV. For 8-36 bases of single- and double-stranded DNA covalently attached to ultra-nanocrystalline diamond, the ratio between in- and out-of-plane components in the best fit simulations to the ellipsometric spectra yields an average tilt angle of the DNA backbone with respect to the surface plane ranging from 45 degrees to 52 degrees . We comment on the physical meaning of the calculated tilt angles. Additional information is gathered from atomic force microscopy, fluorescence imaging, and wetting experiments. The results reported here are of value in understanding and optimizing the performance of the electronic readout of a diamond-based label-free DNA hybridization sensor. 相似文献
30.
Cara L Ryan David C Baranowski Babykumari P Chitramuthu Suneil Malik Zhi Li Mingju Cao Sandra Minotti Heather D Durham Denis G Kay Christopher A Shaw Hugh PJ Bennett Andrew Bateman 《BMC neuroscience》2009,10(1):1-22