ヘリオロドプシン の結晶構造
Wataru Shihoya1, Keiichi Inoue2,3,4,5, Manish Singh2
1Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
Nature
|September 27, 2019
まとめ
ヘリオロドプシン (HeRs) は,新しく発見された微生物ロドプシンで,独特の構造と膜方向性を持っています. 彼らの構造は,新しい網膜結合ポケットと網膜吸収のための横の窓を明らかにします.
科学分野:
- 構造生物学
- 微生物生物化学
- 膜タンパク質
背景:
- ヘリオロドプシン (HeRs) は,最近発見された微生物ロドプシンの一種で,様々な生命体に見られます.
- 他のロドプシンと重要な特性を共有しているにもかかわらず,HERは低い配列同一性と逆の膜方向性を表しています.
- 構造とメカニズムの情報が限られているため,HERの機能と進化の理解が困難でした.
研究 の 目的:
- ヘリオロドプシンの高解像度構造を 培養されていないアーカイオンから決定する
- HeR と他の微生物のロドプシンとの構造的な類似点と違いを明らかにする.
- 光活性化メカニズムとHER構造の機能的影響を調査する.
主な方法:
- HeRの2.4-Å解像度構造を決定するX線結晶学.
- 既知のロドプシン族とHERを比較するための構造分析.
- 生体構造の機能的側面を調査するための生体分析.
主要な成果:
- HeRの全体的な折り畳みはバクテリアホドプシンに似ているが,網膜に結合するポケット残留物には大きな差異がある.
- HeRは,網膜のβイオノン環の上部に独特の横のフェネストレーションを有し,環境網膜捕獲に不可欠です.
- 細胞外半球の水性残留は,陽子とイオンの浸透を防ぐ可能性が高い.
結論:
- 決定されたHeR構造は,微生物のロドプシン構造の多様性に関する重要な洞察を提供します.
- 側面の窓を含むユニークな構造的特徴は,HERの新しい機能的適応を強調しています.
- この研究は,ロドプシン超家族内のHeR機能とその進化的関係に関する理解を深める.
関連する概念動画
Channel Rhodopsins
3.1K
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,...
3.1K
Protein and Protein Structure
86.9K
Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective. They may serve in transport, storage, or membranes; or they may be toxins or enzymes. Their structures, like their functions, vary greatly. They are all, however, amino acid polymers arranged in a linear sequence.
A protein's shape is critical to its function. For example, an enzyme...
A protein's shape is critical to its function. For example, an enzyme...
86.9K
Ionic Crystal Structures
16.8K
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
16.8K
Crystal Field Theory - Octahedral Complexes
30.7K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
30.7K
ATP Synthase: Structure
15.2K
ATP synthase or ATPase is among the most conserved proteins found in bacteria, mammals, and plants. This enzyme can catalyze a forward reaction in response to the electrochemical gradient, producing ATP from ADP and inorganic phosphate. ATP synthase can also work in a reverse direction by hydrolyzing ATP and generating an electrochemical gradient. Different forms of ATP synthases have evolved special features to meet the specific demands of the cell. Based on their specific feature, ATP...
15.2K
Photoreceptors and Visual Pathways
8.8K
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,...
8.8K


