DIFFRACTION EFFICIENCY OF BACTERIORHODOPSIN FILMS FOR HOLOGRAPHY CONTAINING BACTERIORHODOPSIN WILDTYPE BR(WT) AND ITS VARIANTS BR(D85E) AND BR(D96N)
DIFFRACTION EFFICIENCY OF BACTERIORHODOPSIN FILMS FOR HOLOGRAPHY CONTAINING BACTERIORHODOPSIN WILDTYPE BR(WT) AND ITS VARIANTS BR(D85E) AND BR(D96N)
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DOI：
10.1021/j100190a098
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发表时间：
1992-05-28
影响因子：
--
通讯作者：
OESTERHELT, D
中科院分区：
文献类型：
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作者：
HAMPP, N;POPP, A;OESTERHELT, D
Bacteriorhodopsin (BR) films made from purple membranes (PM) containing the wildtype form of BR or one of its variants with single amino acids exchanges Asp96 --> Asn or Asp85 --> Glu were compared with respect to their holographic properties. The dependence of the diffraction efficiency of BR films on the parameters pH, temperature, intensity, initial optical density, and spatial frequency was measured. Increasing the initial optical density of a BR material with a long lifetime of the M intermediate and a low steady-state concentration of all other intermediates, in particular the N and O state, yielded diffraction efficiencies of up to several percent for the technically important read-out wavelength 633 nm. Lowering the temperature of the BR films shifts the maximal diffraction efficiency to lower light intensities. The diffraction efficiency eta of BR films is almost independent of the spatial frequency of the recorded grating in the range 150-1500 mm-1 but decreases to about 80% of the maximal value at 2500 mm-1. Thin layers of PM suspension show essentially lower spatial resolution with strongly nonlinear behavior but could be used for holographic recording with less than 500 mm-1. The BR variant Asp96 --> Asn shows significantly improved optical properties compared with the wildtype form of BR and the variant Asp85 --> Glu. The highest diffraction efficiency of 7% at 633 nm was obtained with a BR-film containing this mutated bacteriorhodopsin at pH 8.0 which had an initial optical density of iOD almost-equal-to 5 at 568 nm and a thickness of 25-mu-m.
