• KSBB Journal
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• v.14 no.6
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• pp.643-650
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• 1999

An artificial photoreceptor composed of bacteriorhodopsin(bR)/flavin complex Langmuir-Blodgett(LB) films was developed by mimicking the human visual system. bR and flavin molecules were deposited onto solid substrate by LB technique, and the deposition of two molecules was proved by UV/VIS absorption spectroscopy and atomic force microscopy(AFM). Based on AFM images and photocurrent generation from the LB films, the optimal conditions for device fabrication were determined. With a series of light illuminations, the generated photocurrent could be detected, and the response characteristics of two molecules could be clearly distinguished from each other. According to the obtained signal shapes, three distinctive regions could be found in the obtained action spectrum. Using a correlation between the photocurrent generation and the wavelength of the input light, it was possible to organize the basic rules to interpret the wavelength of the input light. It is concluded that the proposed artificial photoreceptor would e applicable to the bioelectronic device for color recognition.

• Journal of Photoscience
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• v.3 no.1
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• pp.33-38
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• 1996

The effect of vesicular L-$\alpha$-phosphatidylcholine on the rate of formation of all-trans-N-retinylidene-n-butylamine (3) and on the regeneration kinetics of bacteriorhodopsin pigment from retinal and bacterio-opsin have been studied. An estimate of the relative positions of retinal and n-butylamine in the vesicles has been made by fluoresence quenching experiments. Partition coefficient of retinal and microviscosity of the retinal-binding region have also been determined. The results are discussed in terms of the nature of chemical interaction between retinal and amine in a lipid environment.

• Proceedings of the Korean Biophysical Society Conference
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• 1996.07a
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• pp.23-23
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• 1996

A working molecular model of the angiotensin II type 1 receptor is built based on the seven transmembrane helix structure of the recently refined bacteriorhodopsin atomic coordinates. A multiple copy simultaneous search (MCSS) method is used to search the pharmacophore of angiotensin on the surface of the receptor. Multiple copies of amino acid fragments and organic functional groups are scattered around the possible binding site and the time dependent. (omitted)

• Journal of Photoscience
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• v.9 no.2
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• pp.106-109
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• 2002

Archaeal rhodopsins possess retinal molecule as their chromophores, and their light-energy and light-signal conversions are triggered by all-trans to 13-cis isomerization of the retinal chromophore. Relaxation through structural changes of protein then leads to functional processes, proton pump in bacteriorhodopsin (bR) and transducer activation in phoborhodopsin (pR). It is known that sensory rhodopsins can pump protons in the absence of their transducers. Thus, there should be common and specific features in their protein structural changes for function. In this paper, our r ecent studies on pR from Natronobacterium pharaonis (ppR) by means of low-temperature Fourier-transform infrared (FTIR) spectroscopy are compared with those of bR. In particular, protein structural changes upon retinal photoisomerization are studied. Comparative investigation of ppR and bR revealed the similar structures of the polyene chain of the chromophore and water-containing hydrogen-bonding network, whereas the structural changes upon photoisomerization were more extended in ppR than in bR. Extended protein structural changes were clearly shown by the assignment of the C=O stretch of Asnl05. FTIR studies of a ppR mutant with the same retinal binding site as in bR revealed that the Schiff base region is important to determine their colors.

• Journal of Photoscience
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• v.9 no.2
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• pp.534-536
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• 2002

A halophilic archaeon, Halobacterium salinarum, exhibits phototactic behaviors, by which the organism is guided to red-orange light and evades shorter wavelengths of light. The phototaxis is mediated by two retinal proteins, sensory rhodopsin I and II (SRI and SRII), whose structures are analogous to the cognate protein bacteriorhodopsin, a light-driven proton pump. SRI mediates both attractant and repellent swimming behaviors to orange light and near- UV light, respectively. The two different signaling through the single photoreceptor have been ascribed to the presence of two active structures of SRI (S$\_$373/ and P$\_$520), which are produced upon orange light illumination of SRI and upon subsequent near-UV illumination of S$\_$373/, respectively. In the present study, we have measured the difference FTIR spectra of S$\_$373/ and P$\_$520/ states. In P$\_$520/, the isomeric structure of the chromophore is assignable to all-trans, and the Schiff base of the chromophore is protonated with concomitant deprotonation of Asp76, a combination which allows for the formation of a salt bridge between them. It was suggested that the way of interaction between the Schiff base and the counterion, which is different among SRI$\_$587/, S$\_$373/ and P$\_$520/ and which has been shown to drive the conformational changes in the cognate protein, bacteriorhodopsin, is the key to controlling conformational changes for the attractant and the repellent signaling by SRI.

• Journal of Photoscience
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• v.9 no.2
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• pp.320-322
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• 2002

Archaerhodopsin (aR), a light-driven proton pump found in HaIonubrum sp. aus-l, was crystallized into an octahedral crystal belonging to the space group P4$_3$2$_1$2. It is shown that aR is composed of7 helical segments and an anti-para1leI ${\beta}$ sheet. The main-chain sIrudure of aR is nearly identical to that of bacteriorhodopsin, but a significant structural difference is observed in the protein surface, especially at lipid binding sites.

• Applied Microscopy
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• v.30 no.3
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• pp.241-248
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• 2000

Electron microscopy has used for analysing the structure of protein over 30 years. Bacteriohodopsin and porins are used as examples to illustrate the progress that has recently been made in attaining resolutions which hitherto were regarded as exclusive to the realm of x-ray crystallography. To determine a protein structure used by electron microscopy, one must pass through a number of basic steps including preparation of specimen , data acquisition and data processing.

• Journal of the Korean Applied Science and Technology
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• v.13 no.3
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• pp.119-125
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• 1996

The excess volumes of mixing of benzyl alcohol, ethyl alcohol, halothane, and procaine in vesicle and suspensions of several lipids have been determined at $25^{\circ}C$ using a excess volume dilatometer. The potency of general anesthetics has long been known to be correlated with lipid solubility. Denaturations of the bacteriorhodopsin, which is a sole membrane protein in the purple membrane of Halobacteriun Halobium, were studied by UV/Vis absorption changes. The excess volumes of mixing of benzyl alcohol and procaine in egg lecithin were all found to be negative and this result was confirmed as Miller's supposition.

• Journal of Photoscience
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• v.3 no.2
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• pp.71-76
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• 1996

Anil K. Singh, Mrunalini M. Kapil, Department of Chemistry, Indian Institute of Technology Bombay - 400076, INDIA Purple membrane (PM, $\lambda$$_{max}$ 570 nm) of H. halobium on treatment with sulphuric acid changes its colour to blue ($\lambda$$_{max}$ 608 nm). The purple chromophore can be regenerated from the blue chromophore by exogeneous addition of anions such as CI$^-$ and HPO$_4^{2-}$. Chloride ion is found to be more effective than the dibasic phosphate ion in regenerating the purple chromophore. Nevertheless, one thing common to the anion regeneration is that both CI$^-$ and HPO$_4^{2-}$ show marked pH effect. At pH 1.0 the efficiency of regeneration of the purple chromophore is greater than at pH 2.0, for the same anion concentration. Fluorescence and circular dichroic studies indicate that the proteins do not undergo drastic changes at the secondary' or tertiary structure level and the native structure is preserved during this transition. However, chromophoric-site interactions between retinal and the apoprotein are affected during this colour transition. A molecular mechanism is advanced for this transition.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.348-354
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• 2019

Dipalmitoyl phosphatidyl choline(DPPC), Polyphenol Derivatives, and Hematoxylin-Eosin were directly sonicated in acidic condition for 6 minutes to give clear stock solutions. Absorbtion properties of Polyphenol Derivatives in lecithin vesicle of Diphalmitoyl phosphatidyl choline system at $25^{\circ}C$ have been studied by absorbtion spectroscopy. The equilibrium of Polyphenol Derivatives between monomer and dimer in lecithin vesicles have been existed at low concentration of Polyphenol Derivatives, but oligomer has been formed in vesicle at high concentration of lecithin vesicles. By adding Bacteriorhodopsin(BR) to constant concentration of Polyphenol Derivatives decreased the absorbtion ratio(${\alpha}/{\beta}$) of Polyphenol Derivatives was increased during phase transition of dipalmitoyl phosphatidyl choline. In the presence of column eluted lamella vesicle and mixture of uni- and multilamella aggregates. The differences of rate between column eluted- and mixture were observed, therefore column eluted lamella reaction was represented more catalytic effect. The phase transition temperature of hydrolysis on Dipalmitoyl phosphatidyl choline and Polyphenol Derivatives were measured higher than it of Dipalmitoyl phosphatidyl choline and no Polyphenol Derivatives.