The Effect of Acidic pH on the Spectral Properties of Bacteriorhodopsin

채쾌,Quae Chae Korean Chemical Society 1979 대한화학회지 Vol.23 No.5

Halobacterium halobium으로부터 분리 정제된 퍼플멤브레인을 7.5% 폴리아크릴아미드겔에 혼합시켰다. 이 겔을 사용하여 pH 변화에 따른 흡수 스펙트라와 원편광 이색성스펙트라를 얻었다. pH 7.0에서 보여준 이들 스펙트라의 성질들은 수용액내에 부유하고 있는 퍼플멤브레인으로부터 얻은 것들과 동일하였다. pH 2.7에서는 최대흡광도를 605nm에서 나타내었으며 pH 0.8에서는 565nm에서 보여주었다. 광에 노출되지 않았던 겔의 경우는 광에 노출되었던 겔과는 달리 등흡광점을 보여주었다. pH 2.7과 pH 0.8에서 측정한 원편광 이색성스펙트라는 pH 7.0에서 보여준 bilobed형을 유지하였으며 UV영역에서 분자편광도나 스펙트라의 모양도 pH에 따라 큰 영향을 받지 않았다. pH 2.7에서 생성된 bR605acid 가 퍼플멤브레인의 정상 광화학 순환기 중간 생성물인 $O^{640}$와 유사한 성질을 가진종이 아닐까 추측된다. Purple membrane from Halobacterium halobium was incorporated into 7.5% polyacrylamide gels. Absorption and circular dichroic spectra of purple membrane incorporated with gels were obtained at various pH. The spectra of these gels measured at pH 7.0 were essentially identical with those obtained in the aqueous suspension of purple membrane. Acid titration of the gels showed the transition to a form absorbing at 605nm $(bR_{605}^{acid}$) at pH 2.6, and to a second form at 565nm $(bR_{565}^{acid})$ at pH 0.8. Dark-adapted gels showed an isosbestic point for each transition whereas light-adapted gels did not. Visible CD spectra of $bR_{570}^{LA},\;bR_{305}^{acid}\;and\;bR_{565}^{acid}$ all showed the typical bilobed pattern. CD spectra measured at UV wavelength region were also independent of the variation of pH in terms of molar ellipticity and spectral shape. The protonated species $bR_{605}^{acid}$ may be one of the intermediates formed during the normal photochemical cycle of purple membrane. Most probably, the species $bR_{605}^{acid}$ is considered to be $O^{640}$ in the cycle.

귀리 원형질체에서 피토크롬 작용에 의한 이노시톨 인지질 대사

채쾌,표택물,박문환,조태주 ( Quae Chae,Taeck Yul Pyo,Moon Hwan Park,Tae Ju Cho ) 생화학분자생물학회 1992 BMB Reports Vol.25 No.2

The stimulation of breakdown of phosphatidylinositol 4,5-bisphosphate (PIP₂) by the irradiation of red light (660 nm) was investigated by TLC/autoradiography after incorporation of ^(32)Pi into the oat protoplasts. The highest breakdown of PIP₂ was observed at 5 seconds of incubation after irradiation of red light for 3 seconds. When various wavelengths of light were irradiated, the highest breakdown of PIP₂ was observed at 660 nm which is the absorption maximum of phytochrome Pr form. Inositol 1,4,5-trisphosphate (IP₃) which is a metabolic product of PIP₂ was identified in oat cell by Dowex anion column chromatography, using [³H]-IP₃ as a standard compound. The level of IP₃ was substantially increased by irradiation of red light for 3 seconds. In addition, transient changes of the cytosolic free Ca^(2+) concentration by the red light were also monitored with the fluorescent Ca^(2+) indicator Quin 2 in the presence and the absence of extracellular Ca^(2+). The results suggest that signal transduction via IP₃ and Ca^(2+) may also be feasible in the phytochrome mediated cell responses.

분자 분광학적 방법에 의한 소 심장 Proteolipid 의 구조적 연구

채쾌,경기열 생화학분자생물학회 1991 BMB Reports Vol.19 No.2

UV-VIS difference and fluorescence spectroscopic techniques were employed to probe the structural changes of the membrane proteolipid with the different solvent systems. The purified proteolipid from bovine heart was dissolved in two different solvent systems (water, organic solvent: chloroform-methanol) and various optical spectra with these solvent systems were measured. The number of perturbed tryptophan residues were estimated to be 1.8 in water and 1.2 in organic solvent, respectively. In addition, the higher fluorescence quenching effects on tryptophan residues and/or ANS by acrylamide were observed in water than the one in organic solvent system. The two results strongly support the hydrophobic interaction needed for the oligomerization of the proteolipid in water environment. However, a certain elucidation for the oligomerization state of this protein can not be provided at the moment.

잎담배 성분중 갈색고분자 물질의 분리정제 및 열분해에 관한 연구

채쾌,박지창,Chae, Quae,Park, Ji-Chang 한국연초학회 1980 한국연초학회지 Vol.2 No.1

건조잎담배로부터 단백질로 간주되는 고분자 물질의 gel filtration column chromatography(Sephadex G-75), 투석 그리고 흡착 chromatography의 일종인 brushite column chromatography분리를 시도한 결과, 짙은 갈색의 고분자 물질을 얻었다. Sephadex column에 의한 분리 profile를 보면 분자량이 상이한 두종류의 갈색고분자 물질이 존재함을 확인하였고 brushite column의 분리 profile에 의하면 분자의 전자구조가 다른 두 종류의 고분자가 있음이 나타났다. Burley와 Hicks의 경우 단백질 분해효소에 의한 분해효과를 측정해본 결과, 가장 큰 분해효과를 보인 효소는 chymotrypsin으로 Burley에서 16-30%수준까지 분해현상을 나타내 주었으며 Hicks인 경우 38-57%까지 감소현상을 보여 주었다. Pepsin처리효과는 chymotrypsin처리구와 비슷한 수준을 보였으나 trypsin경우는 매우 낮은 분해현상을 나타냈다. 단백질 분해효소로 처리된 시료의 sephadex column분리 profile을 살펴보면, 분자량이 보다 큰 fraction의 경우 peak가 거의 완전하게 사라짐을 관찰할 수 있으나, 작은 분자량Peak는 약간의 감소현상만을 보여 주었다. 투석후의 갈색 고분자물질을 $300^{\circ}C$에서 연소시킨 경우, 연소전에 관찰할 수 없었던 강한 형광성 물질이 생성되었는데 TLC에 의한 분리후, 이 형광성 물질끈 흡수 스펙트라를 측정해 본 결과, 최대흡수 파장이 265. 275nm(benzene용매)로 나타났으며 스펙트럼 끈 모양이 polynuclear aromatic hydrocarbon(PAH) 계열 화합물의 것과 유사함을 보여 주었다. Gel filtration column chromatography (Sephadex G-75), dialysis an d Brushite column chromatography were carried out to separate the brown pigmented macromolecule from water extracts of the cured leaf tobaccos. The two distinct macromolecules having different molecular weight were separated by the Sephadex column chromatography. Brushite also separated two different species of macromolecules which might have different electronic structures. According to the enzymatic degradation of protein in Burley and Hicks, chymotrypsin showed the best degradation ratio, ie., 16-30% in Burley and 38-57% in Hicks. Similar effect was observed with pepsin. However, very low effect of degradation was revealed with trypsin. The sample treated with the proteolytic enzymes revealed the disappearance of the first peak and the slight decrease of the 2nd peak height in the separation profile of Sephadex. After dialysis, the brown pigmented macromolecule was pyrolyzed at $300^{\circ}C$ and the strongly fluorescent components not identified before pyrolysis were detected with TLC separation. Absorption spectrum of these fluorescent compounds was monitored in benzene and the absorption maxima at 265nm and 275 nm were obtained. Considering absorption maxima and shape of the spectrum, those fluorescent compounds seem to be PAH derivatives.

분자분광학적 방법에 의한 소심장의 proteolipid의 구조연구

경기열, 채쾌 忠北大學校 遺傳工學硏究所 1987 遺傳工學硏究 Vol.1 No.1

본문참고

입체구조 분석에 의한 원생동물 srentor 광수용체 분자의 색소와 단백질간의 결합연구

강영기, 채쾌 忠北大學校 遺傳工學硏究所 1987 遺傳工學硏究 Vol.1 No.1

본문참고

칼슘이온 influx 에 미치는 Cholesterol 과 Phytosterol 의 효과

양덕조,채쾌,김학룡,여종원 생화학분자생물학회 1994 BMB Reports Vol.17 No.3

There is a report that cholesterol and/or some sterols give a positive effect on flowering of plants. Under assumption that the phenomenon can be induced by the enhancement of Ca^(2+) influx through the interaction between cholesterol and the plasma membrane, we carried out the experiment to determine whether the change of the cytosolic Ca ^(2+) concentration could be induced by binding of these compounds to the plasma membrane of oat protoplast. The results show a linear increase of the cytosolic Ca^(2+) concentration as a function of cholesterol concentrations added to the protoplast. However, other phytosterols (sitosterol and stigmasterol) were ineffective. The cytosolic Ca^(2+) concentration was determined by using a calcium specific fluorescent indicator Quin II. Red light effect on Ca^(2+) influx was also investigated in the normal protoplast and the cholesterol bound one. In comparision with the control, a higher influx of Ca^(2+) in the case of the cholesterol bound protoplast was observed when irradiated with red light. However, when the Ca^(2+), influx was blocked by 2 mM EGTA, the cytosolic Ca^(2+) concentration was not changed by cholesterol addition, but slightly increased by irradiation with red light.

귀리 조직의 세포막에서 존재하는 Phospholipase C 의 확인

김혜경,채쾌 생화학분자생물학회 1992 생화학분자생물학회 춘계학술발표논문집 Vol.- No.-

귀리세포 내 피토크롬 작용에 의한 단백질의 탈인산화

박문환,채쾌 ( Moon Hwan Park,Quae Chae ) 생화학분자생물학회 1992 BMB Reports Vol.25 No.1

When the phosphorylation degrees of the two proteins (27 kDa, 32 kDa) in oat cells were examined as a function of red light (660 nm) irradiation time, a slight dephosphorylation (second time scale), phosphorylation 3($lt;2∼3 min) and dephosphorylation ($gt;2∼3 min) were observed, respectively. An inhibition of protein phosphatase was not observed by addition of 10 mM NaF in both cases of dephosphorylation (short and long time irradiations). When we added different concentrations of okadaic acid (1 nM, 15 nM and 1 μM) into the cell, the inhibition effect was only observed at its concentration of 1 μM in either cases (short and long time irradiations). These results suggest that protein phosphatase may be involved in the phytochrome-mediated dephosphorylations and the kind of phosphatase might be PP 2B (calcineurin).

Phytochrome 의 분자구조

한태룡,채쾌 생화학분자생물학회 1986 생화학분자생물학회 소식 Vol.6 No.4