• KSBB Journal
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• 제14권6호
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• pp.643-650
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• 1999

인간시각계의 색채인식기능을 모방하여, 가시광선영역의 빛에 의해 전기신호를 발생시키는 생체분자인 bR과 flavin을 LB막으로 제작하고, 이를 이용하여 개발된 인공감광소자의 색채인식기능을 검증하였다. bR과 flavin은 LB막 상태에서 고유의 특성을 유지할 수 있었으며, 가시광선 영역의 입력광에 대해 안정한 전기신호를 발생시켰다. AFM image와 광전류의 크기를 바탕으로 bR과 flavin LB막의 제작을 위한 최적 조건을 얻을 수 있었다. bR과 flavin을 차례로 적층하여 bR/flavin 복합 LB박막을 제작하였고, 이를 이용하여 감광소자를 제작하였다. 광전류 data를 바탕으로 얻어진 action spectrum을 분석함으로써, 가시광선 영역에서 얻어지는 신호의 형태가 입력되는 빛의 파장 대(색)에 따라 다름을 알 수 있었고, 입력되는 빛의 파장과 측정된 광전류의 크기와의 상관관계를 도출할 수 있었다. 입력되는 빛의 색채(파장)에 따라 나타나는 광전류의 형태 및 크기를 비교하고 제시된 관계식을 이용함으로써, 제안한 소자가 R, G, B 뿐만 아니라 가시광선 영역의 7가지 기본 색에 대해 색채식별능력이 있음을 검증할 수 있었다.

• Journal of Photoscience
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• 제3권1호
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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.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1996년도 정기총회 및 학술발표회
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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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• 제9권2호
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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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• 제9권2호
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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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• 제9권2호
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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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• 제30권3호
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• pp.241-248
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• 2000

전자현미경을 이용한 단백질 구조분석은 약 30여년간 발전되어 왔다. Bacteriorhodopsin과 porin 등의 near atomic resolution의 구조분석은 전자현미경의 발전과 진행을 보여주는 하나의 예로 설명될 수 있다. 전자현미경을 이용한 거대분자의 3차원 구조를 규명하기 위해 필요한 기본과정 즉, 시료준비, 자료수집과 자료처리 등에 대하여 토론하였다.

• 한국응용과학기술학회지
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• 제13권3호
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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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• 제3권2호
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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.

• 한국응용과학기술학회지
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• 제36권1호
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• pp.348-354
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• 2019

Dipalmitoyl phosphatidyl choline(DPPC), Polyphenol 유도체, 그리고 Hematoxylin-Eosin은 5분 동안 산성 상태에서 직접 초음파 처리하여 명확한 표준용액을 제공했다. $25^{\circ}C$에서 DPPC 계의 레시틴소포에서 폴리페놀유도체의 흡수특성은 흡수분광학에 의해 분석하였다. 레시틴소포에서 단량체와 이량체 사이의 폴리페놀유도체의 평형은 폴리페놀유도체의 저농도에서 존재했지만 올리고머는 레시틴소포의 고농도에서 소포안에 형성되었다. 폴리페놀유도체의 일정한 농도에 Bacteriorhodopsin(BR)을 첨가함으로써 DPPC의 상전이동안 폴리페놀유도체의 흡수비율(${\alpha}/{\beta}$)이 감소되었다. 기둥이 있는 곳에 라멜라 소포와 uni- and multilamella 응집체의 혼합물이 존재한다. 용출된 기둥과 혼합물사이의 속도 차이가 관찰되었으므로 기둥 용출된 라멜라반응 보다 촉매 효과를 나타냈다. DPPC 및 폴리페놀유도체에 대한 가수분해의 상전이 온도는 DPPC 및 폴리페놀유도체 보다 높게 측정되었다.