Long holographic lifetimes in bacteriorhodopsin films

Downie, John D.; Timuçin, Doǧan A.; Smithey, D. T.; Crew, Marshall

doi:10.1364/ol.23.000730

Cited by 22 publications

(12 citation statements)

References 3 publications

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“…This allows to achive high concentration of BR (up to 50 %) in nanofilms and avoid aggregation of cell membrane fragments and destruction of BR in the manufacturing process [31]. Embedded into a gelatin matrix BR-containing PM fragments are durable (10 4 h) and resistant to solar light, the effects of oxygen, temperatures greater than 80 ºC (in water) and up to 140 ºC ( in air), pH = 112, and action of most proteases [32]. The dried PM are stacked on top of each other, focusing in the plane of the matrix, so that a layer with 1 m thickness contains about 200 monolayers [33].…”

Section: Resultsmentioning

confidence: 99%

Metabolism, Physiology and Biotechnological Applications of Halobacteria

Mosin¹,

Ignatov²

2015

European Journal of Molecular Biotechnology

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Halophiles (lat. "salt-loving") is the taxonomic group of extreme aerobic obligate Gramnegative microorganisms that live in conditions of high salinity -in the seas, salt lakes, saline soils etc. These microorganisms are known to reddish patina on products, preserved with using large quantities of salt (NaCl). Halophiles were isolated for the first time at the beginning of the XX century from the marine flora estuary mud, but their systematic study was started only at the end of the second decade of the XX century. The internal environment of the human body is not suitable for existence of halobacteria, since none of them are known to have pathogenic forms. Halobacteria have great practical potential for using in molecular bioelectronics and bionanotechnology due to their unique ability to convert the energy of sunlight into electrochemical energy of protons H + due to the presence in their cells a special photo transforming retinal containing integral protein -bacteriorhodopsin, the mechanism of action of which has been currently studied in detail. This article describes the characteristics of the metabolism and physiology of halophilic bacteria, as well as a method of biosynthesis and preparation of bacteriorhodopsin from purple membranes of cells of the extreme photoorganotrophic halobacterium Halobacterium halobium.

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Section: Resultsmentioning

confidence: 99%

Metabolism, Physiology and Biotechnological Applications of Halobacteria

Mosin¹,

Ignatov²

2015

European Journal of Molecular Biotechnology

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“…While both proteins offer an improved holographic efficiency, D85E/D96Q exhibits the highest efficiency of any BR mutant explored to date. 10,28,37,50,66 …”

Section: Resultsmentioning

confidence: 99%

Photochromic Bacteriorhodopsin Mutant with High Holographic Efficiency and Enhanced Stability via a Putative Self-Repair Mechanism

Ranaghan

Greco

Wagner

et al. 2014

ACS Appl. Mater. Interfaces

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The Q photoproduct of bacteriorhodopsin (BR) is the basis of several biophotonic technologies that employ BR as the photoactive element. Several blue BR (bBR) mutants, generated by using directed evolution, were investigated with respect to the photochemical formation of the Q state. We report here a new bBR mutant, D85E/D96Q, which is capable of efficiently converting the entire sample to and from the Q photoproduct. At pH 8.5, where Q formation is optimal, the Q photoproduct requires 65 kJ mol-1 of amber light irradiation (590 nm) for formation and 5 kJ mol-1 of blue light (450 nm) for reversion, respectively. The melting temperature of the resting state and Q photoproduct, measured via differential scanning calorimetry, is observed at 100 °C and 89 °C at pH 8.5 or 91 °C and 82 °C at pH 9.5, respectively. We hypothesize that the protein stability of D85E/D96Q compared to other blue mutants is associated with a rapid equilibrium between the blue form E85(H) and the purple form E85(−) of the protein, the latter providing enhanced structural stability. Additionally, the protein is shown to be stable and functional when suspended in an acrylamide matrix at alkaline pH. Real-time photoconversion to and from the Q state is also demonstrated with the immobilized protein. Finally, the holographic efficiency of an ideal thin film using the Q state of D85E/D96Q is calculated to be 16.7%, which is significantly better than that provided by native BR (6–8%) and presents the highest efficiency of any BR mutant to date.

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“…This allows to achive high concentration of BR (up to 50 %) in nanofilms and avoid aggregation of membrane fragments and destruction of BR in the manufacturing process [23]. Embedded in a gelatin matrix PM fragments are durable (10 4 h) and resistant to solar light, the effects of oxygen, temperatures greater than 80 0 C (in water) and up to 140 0 C (in air), pH = 112, and action of most proteases [24]. Dried PM are stacked on top of each other, focusing in the plane of the matrix, so that a layer with 1 m thickness contains about 200 monolayers [25].…”

Section: Resultsmentioning

confidence: 99%

Studying of Phototransformation of Light Signal by Photoreceptor Pigments - Rhodopsin, Iodopsin and Bacteriorhodopsin

Ignatov¹,

Mosin²

2014

Nanotechnology Research and Practice

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This review article views predominately the structure and function of animal and bacterial photoreceptor pigments (rhodopsin, iodopsin, bacteriorhodopsin) and their aspects of nano-and biotechnological usage. On an example of bacteriorhodopsin is described the method of its isolation from purple membranes of photo-organotrophic halobacterium Halobacterium halobium by cellular autolysis by distilled water, processing of bacterial biomass by ultrasound at 22 KHz, alcohol extraction of low and high-weight molecular impurities, cellular RNA, carotenoids and lipids, the solubilization with 0,5 % (w/v) SDS-Na and subsequent fractionation by methanol and gel filtration chromatography on Sephadex G-200 Column balanced with 0.09 M Tris-borate buffer (pH = 8,35) with 0,1 % (w/v) SDS-Na and 2,5 mM EDTA. Within the framework of the research the mechanism of color perception by the visual analyzer having the ability to analyze certain ranges of the optical spectrum, as colors was studied along with an analysis of the additive mixing of two colors. It was shown that at the mixing of electromagnetic waves with different wavelengths, the visual analyzer perceive them as separate or average wave length corresponding to mix color.Keywords: vision; rhodopsin; iodopsin; bacteriorhodopsin; additive color mixing. IntroductionVision (visual perception) is a process of psycho-physiological processing of the images of surrounding objects, carried out by the visual system, which allows to get an idea of the size, shape and color of surrounding objects, their relative position and distance between them. By means of this animals can receive 90 % of all incoming information to the brain.The function of the visual system is carried out through various interrelated complex structures designated as visual analyzer, consisting of a peripheral part (retina, optic nerve, optic tract) and the central department of combining stem and subcortical centers of the midbrain, as

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Long holographic lifetimes in bacteriorhodopsin films

Cited by 22 publications

References 3 publications

Metabolism, Physiology and Biotechnological Applications of Halobacteria

Metabolism, Physiology and Biotechnological Applications of Halobacteria

Photochromic Bacteriorhodopsin Mutant with High Holographic Efficiency and Enhanced Stability via a Putative Self-Repair Mechanism

Studying of Phototransformation of Light Signal by Photoreceptor Pigments - Rhodopsin, Iodopsin and Bacteriorhodopsin

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