Excited States of Photoreceptor Molecules (I). Peridinin

송필순,이태영,Pill-Soon Song,Tae Young Lee Korean Chemical Society 1979 대한화학회지 Vol.23 No.5

The electronic spectrum of marine dinoflagellate antenna pigment, peridinin, has been described in terms of PPP SCF MO CI computations and fluorescence polarization of the peridinin component in photosynthetic pigment complex of Amphidinium carterae. The main absorption band at 470 nm, $^1B{\leftarrow}A$, is polarized nearly along the long molecular axis. There appear to be two ${\pi}{\rightarrow}{\pi}^*$ transitions (C and $D{\leftarrow}A$) in the socalled "cis" peak region, and they are polarized roughly parallel to the main $B{\leftarrow}A$ absorption. In addition, we have found that the carbonyl group undergoes very 1ittle reorganization of the electronic structure in going from the ground to the $^1B$ excited states of peridinin, while the allenic group shows a strong charge transfer tendency in producing an electron-deficient allente allene group in the excited state. 바닥 말무리 dinoflagellate의 광합성 에너지 수용 색소인 peridinin의 전자 흡수스펙트럼을 PPP SCF MO 계산결과와 형광 편광 실험결과에 견주어 분석하였다. 청색광 부위의 흡수띠 (470 nm)는 $B{\leftarrow}A$ 천이에 대응하여 분자의 장축과 거의 평행 방향으로 편광되어 있음이 예측된다. 소위 "cis peak" 영역의 근자외선 흡수띠는 두개의 비교적 약한 ${\pi}{\rightarrow}{\pi}^*$천이 $(C{\leftarrow}A$와 $D{\leftarrow}A)$에 기인하며 그 편광축은 $^1B{\leftarrow}A$편광축 방향과 근접되어 있음이 MO 계산과 편광 측정에 의해 추정되었다. 그리고 락톤 카르보닐 원자단의 전자구조는 $^1B$ 상태에서도$^1A$ 상태 (ground state)에 비해서 과히 변화함이 없으나, allene기는 charge transfer적 성격을 농후하게 띠고 있어서 들뜬상태에서는 allene기가 전자결핍상태가 되는 것이 예측된다.

Molecular Structure of Phytochrome as Probed by Intrinsic Tryptophan Phosphorescence of Degraded 59 Kilodalton Chromopeptide

한태룡,송필순,Hahn, Tae-Ryong,Song, Pill-Soon Korean Society for Biochemistry and Molecular Biol 1987 한국생화학회지 Vol.20 No.1

Phytochrome의 chromophore와 apoprotein의 분자 구조 및 배열을 알아보기 위해 분해된 small phytochrome (59 kD)의 트립토판 인광을 측정하였다. 인광수명값은 비교적 짧았으며 Pr형 (0.21초)과 Pfr형 (0.19초)간의 차이는 거의 없었다. 또한 트립토판에서 chromophore로의 에너지 전달은 관찰되지 않았다. 이는 large phytochrome (118 kD)에서 트립토판으로부터 Pr chromophore로 에너지가 효과적으로 전달된다는 사실 (Sarkar & Song. 1982)과는 상반된다. 이상의 결과로부터 proximal 트립토판잔기가 55 kD nonchromophore domain에 존재하며 이 부분이 단백분해 효소에 의해 잘려나가 small phytochorme 산불이 생성되는 것으로 믿어진다. The intrinsic phosphorescence of the degraded small phytochrome which has a molecular mass of 59 kilodalton(kD) was measured to probe the chromophore and apoprotein topography of phytochrome. Phosphorescence life times of tryptophan(Trp) residues of the small phytochrome show relatively short values and virtually no differences between the red light absorbing, Pr(0.21 s) and far red light absorbing, Pfr(0.19 s) forms. No delayed fluorescence from the chromophore upon excitation of Trp residues was observed, indicating that there is no energy transfer from the Trp(s) to the hromophore. The large phytochrome (118 kD) showed efficient energy transfer from the proximal Trp(s) to the Pr chromophore and a delayed fluorescence from the Pr hromophore upon excitation of Trps at 290 nm (Sarkar and Song, 1982). Results suggest that the 55 kD nonchromophore domain where the proximal Trp(s) resides is removed in the small phytochrome by proteolytic degradation.

태양에너지를 채취하는 색소단백질들의 분자 토포그라피와 에너지전달현상

송필순(Pill Soon Song),정진(Jin Jung) 한국응용생명화학회 1980 Applied Biological Chemistry (Appl Biol Chem) Vol.23 No.1

The light harvesting pigment proteins of dinoflagellates exhibit essentially 100 efficient energy transfer from carotenoid (peridinin) to chlorophyll a within the antenna pigment complexes. The high efficiency of solar energy harvesing(particularly blue light) for photosynthesis in dinoflagellates is attributable to the unique molecular topography of peridinin and chlorophyll a within the protein crevice. The mechanisms of energy transfer from carotenoids to chlorophyll in higher plants have also been discussed in comparison with the dinoflagellate antenna pigment complexes. As an example of solar energy harvesting, particularly red light, for photosynthesis in algae, the molecular topography and energy transfer in the photosynthetic accessory pigment protein, Chroomonas phycocyanin, have also been discussed.

Molecular Aspects of Some Photobiological Receptors

송필순 ( Pill Soon Song ) 한국응용생명화학회 1977 Applied Biological Chemistry (Appl Biol Chem) Vol.20 No.1

The photobiological receptors of phototactic, phototropic, and photomorphogenic responses of various organisms have been described in terms of spectroscopic, photophysical and photochemical properties which may be relevant in elucidating the energy transduct ion mechanisms) in photobiology. The photoreceptors discussed include carotenoids, flavins, stentorin and phytochrome. Although the molecular modes of their photobiological action still remain largely unexplained, it is possible to suggest several primary molecul ar processes of the photoreceptors in eliciting responses of various organisms to light.

무화과와 쎌러리의 향기 성분 Psoralen과 발암제 Aflatoxin의 광 생물학적 영향

송필순(Pill Soon Song) 한국식품과학회 1979 한국식품과학회지 Vol.11 No.4

Urea 에 의해 변성된 Phytochrome 의 분광학적인 성질

김인수,송필순 ( In Soo Kim,Pill Soon Song ) 생화학분자생물학회 1984 BMB Reports Vol.17 No.1

The molecular nature of urea-treated phytochrome has been studied spectroscopically using a highly purified large phytochrome. The spectral informations of absorption, CD and fluorescence are extended to the far-UV region. The absorption and CD spectra in the chromophoric region showed that the Pfr spectra were perturbed more drastically than the Pr spectra toward urea denaturation. The CD in the peptide absorption region, and absorption and fluorescence emission of tryptophan / tyrosine residues of phytochrome indicated that the conformation of the native state was the same for both forms of phytochrome, and that susceptibilities of protein unfolding remained the same for the both forms during denaturation. These observations suggest that protein chromophore interaction sites of the both forms have different sensitivities to urea denaturation, but that the conformational susceptibilities of their protein moieties to urea are the same. Partial denaturation of phytochrome with 3M urea oriented the chromophore to have a higher phototransformation rate by blue light irradiation.

Hydrophobic Sites on the Protein Surfaces of the Pr and Pfr Forms of Phytochrome

김인수,송필순,Kim, In-Soo,Song, Pill-Soon Korean Society for Biochemistry and Molecular Biol 1987 한국생화학회지 Vol.20 No.2

Phytochrome의 활성형인 Pfr과 불활성형인 Pr의 단백질 표면에 있는 소수성 부위를 $\alpha$-chymotrypsin에 의한 부분가수분해와 SDS에 의한 변성으로 연구하였다. Phytochrome을 효소와 60:1 (w/v)의 비율로 가수분해 할때 Pr형의 660 nm 흡광도는 20%가 감소하는 반면 Pfr 형의 730 nm 흡광도는 완전히 소멸하였다. $\alpha$-chymotrypsin의 가수분해물을 SDS-gel 전기영동으로 검정한 peptide 양상으로 보아서 Pr형이 가수분해속도가 빠르지만 단백질표면의 소수성 부위 는 Pfr 형에서 더욱 다양하게 분포되어 있었다. $\alpha$-Chymotrypsin 가수분해의 초기 생성물인 chromopeptide는 non-chromopeptide보다 가수분해 속도가 느리게 나타났다. Pfr 형이 Pr형에 비하여 가수분해 속도가 느림에도 불구하고 흡광 spectrum이 급격히 변화하는 것은 Pr 형에서 Pfr형으로 광전환 할때 단백질과 색소의 결합주변에 소수성 부위가 생성되었기 때문이고 이 소수성 부위는 phytochrome의 활성부위와 관련이 있을 것으로 생각되었다. The nature of hydrophobic sites on the protein surfaces of the Pr and Pfr forms of phytochrome (118 kDa) has been studied by spectroscopic and electrophoretic properties of phytochrome that was partially digested with $\alpha$-chymotrypsin. The enzyme digestion bleached the Pfr spectrum completely at a 1:60 (w/v) enzyme to substrate ratio, while the Pr absorbance was decreased by 20%. SDS-gel electrophoresis of the $\alpha$-chymotrypsin-digested phytochrome showed that, at an early stage of digestion, the rate of hydrolysis was faster in the Pr form and the electrophoretic pattern of polypeptide digests was more complicated in the Pfr form than in the Pr form. The chromopeptide domain was more resistant to $\alpha$-Chymotrypsin digestion than the nonchromophore domain. The pronounced susceptibility of the Pfr spectrum to $\alpha$-Chymotrypsin was considered to be the action of the enzyme on hydrophobic site(s) at the chromophore vicinity that was newly developed by phototransformation from the Pr form to the Pfr form.

Spectroscopic Characterization of Pr and Pfr Forms of Phytochrome Denatured by Urea

김인수,송필순,Kim, In-Soo,Song, Pill-Soon 생화학분자생물학회 1984 한국생화학회지 Vol.17 No.1

순수한 phytochrome을 요소로 변성시킬 때 나타나는 흡광도, CD 및 형광동의 분광학적인 변화를 관찰하여 활성형인 Pfr과 비활성형인 Pr간의 분자 구조의 차이를 연구하였다. Phytochrome을 요소로 처리할 때 가시광선 (300~800nm파장)에서의 CD와 흡광도는 Pfr형이 Pr형에 비하여 큰 변화를 받고 있으나, 자외선 (200~300nm파장)에서의 흡광도, CD 및 형광의 변화는 두 형태간에 동일하였다. 가시광선에서의 Pr형과 pfr형의 감수성 차이는 요소에 대하여 색소-단백질의 상호작용이 서로 다른 영향을 받기 때문이다. 그러나 peptide의 흡광파장인 자외선에서의 결과는 두 형태간에 요소에 대한 단백질의 변성 정도 및 단백질의 구조에는 차이가 없음을 나타내고 있다. Phytochrome을 요소로 부분변성시켰을 때는 청색광(380nm 파장)에 의한 Pr형에서 Pfr형으로의 광전환이 촉진된다. The molecular nature of urea-treated phytochrome has been studied spectroscopically using a highly purified large phytochrome. The spectral informations of absorption, CD and fluorescence are extended to the far-UV region. The absorption and CD spectra in the chromophoric region showed that the Pfr spectra were perturbed more drastically than the Pr spectra toward urea denaturation. The CD in the peptide absorption region, and absorption and fluorescence emission of tryptophan / tyrosine residues of phytochrome indicated that the conformation of the native state was the same for both forms of phytochrome, and that susceptibilities of protein unfolding remained the same for the both forms during denaturation. These observations suggest that protein chromophore interaction sites of the both forms have different sensitivities to urea denaturation, but that the conformational susceptibilities of their protein moieties to urea are the same. Partial denaturation of phytochrome with 3M urea oriented the chromophore to have a higher phototransformation rate by blue light irradiation.

분해된 59 kD chromopeptide 의 트립토판 인광측정에의한 phytochrome 의 분자구조

한태룡,송필순 ( Tae Ryong Hahn,Pill Soon Song ) 생화학분자생물학회 1987 BMB Reports Vol.20 No.1

The intrinsic phosphorescence of the degraded small phytochrome which has a molecular mass of 59 kilodalton(kD) was measured to probe the chromophore and apoprotein topography of phytochrome. Phosphorescence life times of tryptophan(Trp) residues of the small phytochrome show relatively short values and virtually no differences between the red light absorbing, Pr(q.21 s) and far red light absorbing, Pfr(0.19 s) forms. No delayed fluorescence from the chromophore upon excitation of Trp residues was observed, indicating that there is no energy transfer from the Trp(s) to the chromophore. The large phytochrome (118 kD) showed efficient energy transfer from the proximal Trp(s) to the Pr chromophore and a delayed fluorescence from the Pr chromophore upon excitation of Trps at 290 ㎚ (Sarkar and Song, 1982). Results suggest that the 55 kD nonchromophore domain where the proximal Trp(s) resides is removed in the small phytochrome by proteolytic degradation.

Pr 형과 Pfr 형 Phytochromd 의 단백질 표면의 소수성부위

김인수,송필순 ( In Soo Kim,Pill Soon Song ) 생화학분자생물학회 1987 BMB Reports Vol.20 No.2

The nature of hydrophobic sites on the protein surfaces of the Pr and Pfr forms of phytochrome (118 kDa) has been studied by spectroscopic and electrophoretic properties of phytochrome that was partially digested with α -chymotrypsin. The enzyme digestion bleached the Pfr spectrum completely at a 1:60 (w/v) enzyme to substrate ratio, while the Pr absorbance was decreased by 20%. SDS-gel electrophoresis of the α -chymotrypsin-digested phytochrome showed that, at an early stage of digestion, the rate of hydrolysis was faster in the Pr form and the electrophoretic pattern of polypeptide digests was more complicated in the Pfr form than in the Pr form. The chromopeptide domain was more resistant to α -chymotrypsin digestion than the nonchromophore domain. The pronounced susceptibility of the Pfr spectrum to α -chymotrypsin was considered to be the action of the enzyme on hydrophobic site(s) at the chromophore vicinity that was newly developed by phototransformation from the Pr form to the Pfr form.