• Bulletin of the Korean Chemical Society
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• 제10권1호
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• pp.69-71
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• 1989

Effects of SDS and temperature on the conformational changes of bacteriorhodopsin were studied using a, b, c bands of bacteriorhodopsin. In the SDS denaturation, bacteriorhodopsin in purple membrane was more labile than bacteriorhodopsin reconstituted into PC vesicles. These rather interesting results may be understood by effective SDS concentration in lipid layer.

• Journal of Photoscience
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• 제9권2호
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• pp.118-121
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• 2002

A state of bacteriorhodopsin at high temperature was studied by various spectral measurements. The stability measurements indicated that the onset temperature of the denaturation was 70$^{\circ}C$ in the dark and 60$^{\circ}C$ under illumination. The reactivity of hydroxylamine with the Schiff's base also significantly increased in the temperature range between 60 and 70$^{\circ}C$. A spectral band at about 470 nm appeared in the temperature range higher than 60$^{\circ}C$. The circular dichroism spectra in the visible region started to change from a bilobed exiton type to a positive band at about 60$^{\circ}C$, suggesting that the two-dimensional configuration of bacteriorhodopsin molecules changed from crystalline to amorphous. All the measurements suggested a new state between 60 and 70$^{\circ}C$ in which bacteriorhodopsin is stable only in the dark.

• KSBB Journal
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• 제13권3호
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• pp.268-271
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• 1998

Bacteriorhodopsin in the purple membrane (PM) of halobacteria has recently been attracting much attention to be used as a component of molecular electron device and optical computers. In order to increase the productivity of bacteriorhodopsin in high cell density cultures of Halobacterium halobium R1, an internal membrane cell-retention bioreactor system was employed. As a result, the production of cell mass at OD660 of 12 and of bacteriorhodopsin at 125-130 mg/L were obtained using the internal membrane bioreactor system at a dilution rate of 0.066 hr-1. The productivity achieved by the internal membrane system (0.7 mg/L$.$hr) was 3.5-fold higher than that obtained by the corresponding batch cultivations (0.2 mg/L$.$hr).

• 센서학회지
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• 제9권3호
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• pp.208-212
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• 2000

A protein based vision biomembrane was fabricated by adsorbing bacteriorhodopsin into electrochemically polymerized polypyrrole film substrate mainly through strong electrostatic interaction. The immobilized bacteriorhodopsin on the polypyrrole film was demonstrated by SEM and SRET. The light signal transducing function from the bacteriorhodopsin which was adsorbed into Polypyrrole film was evaluated by electroretinogram(ERG). A wave form analysis of the electroretinogram indicated that the adsorbed bacteriorhodopsin retained its activity and light signal was obtained from the protein for at least one month.

• Journal of Photoscience
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• 제9권2호
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• pp.299-301
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• 2002

Recent denaturation experiments of bacteriorhodopsin (bR) in the dark and under illumination at high temperatures revealed that irreversible thermal bleaching occurs above ~ 70°C and the preceding reversible structural changes in the dark above 60°C are closely related to irreversible photobleaching observed in the same temperature range (Yokoyama et al. (2002). J Biochem. 131,785). In this study, structural properties of bacteriorhodopsin (bR) at high temperatures were extensively probed by hydroxylamine reactivity with the Schiff base in the dark and hydrogen-deuterium (H-D) exchange in the peptide groups. In the Arrhenius plot from kinetics measurements of the hydroxylamine reaction, a good linear relationship between the reaction time constant and the inverse of the absolute temperature was observed below 60°C, while significant increase started above 60°C, suggesting that remarkable increase in water accessibility of the Schiff base in the temperature region. FT-IR spectroscopic studies on the H-D exchange suggested increase in the deuterium exchanges rate of the peptide hydrogen in the same temperature region.

• 대한화학회지
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• 제37권11호
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• pp.974-977
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• 1993

• 대한화학회지
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• 제42권2호
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• pp.143-149
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• 1998

마취제를 purple membrane내 bacteriorhodopsin(bR)에 가했을 때 570nm 흡수 띠는 480nm로 이동한다. 마취제에 의해 유도된 분광학적 변화는 가역적이다. 이러한 평형의 겉보기 pKa(6.3)는 bR에 분산된 마취제의 성질에 의존한다. bR의 전기배향 측정은 비교적 작은 전기장에서도 쉽게 달성될 수 있었으며 이때의 배향각도는 60°이었다. 그러나 마취제로 처리한 bR은 이러한 변화를 관측할 수가 없다. 이들 결과들은 마취제에 의해 발색단과 발색단 주변의 단백질 구조의 민감한 변화가 단백질 매트릭스의 전하를 띈 잔기들의 공간적 배향에 영향을 준 것으로 보인다.

• 한국광학회지
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• 제13권5호
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• pp.414-420
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• 2002

본 연구에서는 bacteriorhodopsin(bR)이 첨가된 고분자 박막을 이용하여 광 논리회로 특성을 구현하였다. bR은 분광학적으로 구분되는 몇 단계의 중간단계로 구성된 복잡한 참순환 과정을 수반하고 있다. 우리는 bR의 광순환 과정중 B상태와 M상태의 흡수도 변화를 고려하여 He-Ne 레이저(632.8 nm)와 He-Cd 레이저(413 nm) 이용하여 광학적 논리회로를 구현하였다. 또한 B상태와 K상태간의 흡수 스펙트럼을 고려하여 He-Ne 레이저(632.8 nm)와 Nd-YAG 레이저의 제2고조파인 532 nm를 이용하여 고속 AND logic gate를 구현하였다.

• 대한화학회지
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• 제36권4호
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• pp.504-510
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• 1992

L-${\alpha}$-lecithin vesicle, bacteriorhodopsin(BR) 그리고 인지질로 재구성된 BR vesicle(InBR vesicle)의 각각의 수용액에서 methylene blue(MB)의 흡수성질을 $20^{\circ}C$에서 $60^{\circ}C$까지 흡수분광법으로 측정하였다. 인지질 vesicle에서 묽은 농도의 MB는 단위체와 이합체 사이에 평형을 이루었고, 고농도의 MB는 oligomer를 형성하였다. 대부분의 경우에 지질(vesicle)의 농도가 매우 높아지면 점점 단위체로 재분배 되었다. 일정한 MB 농도에 BR를 첨가할 때 흡광도비(${\alpha}/{\beta}$)는 감소되며 oligomer가 형성되었다. MB는 InBR vesicle의 상전이 온도 부근에서 흡광도비(${\alpha}/{\beta}$)가 증가했으나 인지질 vesicle에서는 상전이에 무관했다. 이것은 InBR vesicle 표면 위에서 회합하는 MB 분자들은 지질의 상전이에 영향을 받아 단위체로 재분배되는 것으로 사료된다.

• Journal of Photoscience
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• 제9권2호
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• pp.296-298
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• 2002

Irreversible photobleaching of bacteriorhodopsin (bR), namely denaturation induced by illumination of visible light, was investigated by absorption kinetic measurements. The denaturation kinetics revealed that light illumination significantly enhanced the structural decay of bR. The kinetic analyses showed that the molecular structure of bR denatures according to a single-exponential decay, whereas irreversible photobleaching has two decay components. The decay constant of the slow component of photobleaching is almost same as that in the dark. An Arrhenius plot of the denaturation kinetic constants for the fast and slow components showed similar activation energies of approximately 19 kcal/mol.