150秒の時間解像度のX線結晶学でタンパク質の機能を観察する
Friedrich Schotte1, Manho Lim, Timothy A Jackson
1Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Science (New York, N.Y.)
|June 21, 2003
まとめ
ミオグロビン (Mb) L29F変異タンパク質の急速な構造変化をX線 difraksionを用いて観察しました. このミュータントは,ワイルドタイプのMbよりも1000倍短いCO中間寿命を示し,ダイナミックなタンパク質の動きを明らかにしています.
科学分野:
- 構造生物学 構造生物学とは
- バイオフィジックス 生物物理学
- タンパク質のダイナミクス
背景:
- マイオグルビン (Mb) は酸素輸送に不可欠です.
- Mbのリガンド結合と放出ダイナミクスを理解することは,タンパク質の機能の鍵です.
- 以前の研究では,これらの動態に関する高解像度,時間解像度データがなかった.
研究 の 目的:
- ミオグロビンL29F変異体のピコ秒スケールの構造進化を調査する.
- L29F MbCO.から放出される一酸化炭素 (CO) のメカニズムを解明する.
- タンパク質の構成の変化とリガンドの動態を相関させるため.
主な方法:
- ピコ秒時間解像度X線微分は1.8アングストーム解像度.
- フラッシュフォトライズされたL29F MbCO.CO.の時間解像度のある中赤外線スペクトロスコーピー.
- 電子密度マップを分析して,一時的な状態を視覚化します.
主要な成果:
- L29F Mb変異体のフレームごとに観察された構造的進化.
- 140psの寿命を持つ一時的なCO中間物質を特定し,野生型よりも1000倍短かった.
- CO放出中に劇的な形状の変化と相関するサイドチェーン運動を明らかにした.
結論:
- L29F変異は,マイオグルビンからのCO解離を著しく加速します.
- タンパク質の構成の変化は,デオキシ状態とカルボキシ状態の間の変化をはるかに超えています.
- サイドチェーンダイナミクスは,ミオグロビンからのリガンドの急速な排出に重要な役割を果たします.
関連する概念動画
02:18X-ray Crystallography
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
01:10X-ray Diffraction of Biological Samples
X-ray diffraction or XRD is an analytical tool that utilizes X-rays to study ordered structures such as crystalline organic and inorganic samples, polycrystalline materials, proteins, carbohydrates, and drugs.
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...
01:19Protein Dynamics in Living Cells
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...