関連する実験動画
Updated: Jul 5, 2026

06:48
CD Spectroscopy to Study DNA-Protein Interactions
Published on: February 10, 2022
固有のキラリティは,ロドプシンの可視/紫外線に近いCDスペクトルを支配する
Gennaro Pescitelli1, Narasimha Sreerama, Piero Salvadori
1Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Pisa, Via Risorgimento 35, I-56126 Pisa, Italy.
Journal of the American Chemical Society
|April 19, 2008
まとめ
ロドプシンにおける可視および近紫外線の円形二重化 (CD) 帯は,主に網膜染色体 (retPSB) のプロトン化シフ基の固有のキラリティから生じる. タンパク質群との相互作用による寄与は,特にベータバンドの寄与は小さい.
科学分野:
- バイオフィジックス 生物物理学
- コンピューティング・ケミストリー
- スペクトル顕微鏡検査です.
背景:
- ロドプシンにおける可視 (アルファ) と近紫外線 (ベータ) の円形の二重化 (CD) 帯の起源については,依然として議論されている.
- 具体的には,これらの帯が網膜染色体 (retPSB) のプロトン化シフ基の固有キラリティによるものなのか,それとも染色体と周囲のタンパク質残留物の相互作用によるものなのかは不明である.
研究 の 目的:
- ロドプシンのCDスペクトルに内在する染色体キラリティとタンパク質結合の貢献を計算的に決定する.
- ロドプシンで観察されたアルファおよびベータCD帯の主要な源を明らかにする.
主な方法:
- 時間依存密度関数理論 (TDDFT) とZINDO法を使用して retPSB染色体の固有CDを計算しました.
- 第一の perturbation 理論を用いて, retPSB トランジションとタンパク質クロモフォール トランジション (pi-pi* と n-pi*) の間のカップリングの影響を評価した.
- ロドプシンの4つの結晶構造から派生した8つの構造の計算を行い,オカダのTDDFTとオカダのTDDFTを計算した. (1U19) 構造により,最も信頼性の高い結果が得られます.
主要な成果:
- アルファ・バンドとベータ・バンドの固有回転強度は,それぞれ0.62 +/- 0.00 DBMと0.90 +/- 0.03 DBMとして計算されました.
- タンパク質群との結合による貢献は,α帯では -0.32 +/- 0.05 DBM,β帯では -0.01 +/- 0.03 DBMであった.
- この結果は, retPSB染色体の内在的なキラリティが,両方のCD帯の支配的要因であることを示している.
結論:
- ロードプシンの可視および近紫外線CD帯は,主に retPSB染色体の固有のキラリティによって決定されます.
- retPSB染色体とタンパク質群の結合効果の貢献は,アルファ帯ではかなり小さく,β帯ではほとんどない.
関連する概念動画
Channel Rhodopsins
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Chirality in Nature
Chirality is the most intriguing yet essential facet of nature, governing life’s biochemical processes and precision. It can be observed from a snail shell pattern in a macroscopic world to an amino acid, the minutest building block of life. Most of the snails around the world have right-coiled shells because of the intrinsic chirality in their genes. All the amino acids present in the human body exist in an enantiomerically pure state, except for glycine - the sole achiral amino acid. The...
Prochirality
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...
Properties of Enantiomers and Optical Activity
It is essential to understand the difference between chiral and achiral interactions and the implications thereof in optical activity and their applications. Just as our feet, which are chiral, interact uniquely with chiral objects, such as a pair of shoes, but identically with achiral socks, enantiomers of a molecule exhibit different properties only when they interact with other chiral media. An example of a significant implication from this facet is the phenomenon known as optical activity,...
Chirality
Chirality is a term that describes the lack of mirror symmetry in an object. In other words, chiral objects cannot be superposed on their mirror images. For example, our feet are chiral, as the mirror image of the left foot, the right foot, cannot be superposed on the left foot.
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...

