Fyn SH3の密度が低い折り畳み付いた中間物質で,リラクゼーション分散型NMRが特徴です
Dmitry M Korzhnev1, Xavier Salvatella, Michele Vendruscolo
1Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
Nature
|July 30, 2004
まとめ
研究者らは核磁共振 (NMR) 光譜を用いて,低集団のタンパク質折り畳み中間物質を特定した. この画期的な発見により,タンパク質の折りたたみ動力学,エネルギー学,および中間構造の詳細な特徴づけが可能になった.
科学分野:
- バイオケミストリー バイオケミストリー
- 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
背景:
- 生物化学プロセスは,しばしば,反応機構にとって極めて重要な,一時的な,低密度の中間物質を含みます.
- これらの中間物質を研究することは困難ですが,重要な力学的な洞察を提供します.
- 生物学的構造の獲得のためのモデルであるタンパク質の折り畳みには,しばしばそのような一時的な状態が含まれます.
研究 の 目的:
- タンパク質の折りたたみにおける低集団の折りたたみ中間物質を特定し,特徴づけること.
- FynチロシンキナーゼからSH3ドメインの変異の折り畳み行動を調査する.
- タンパク質エネルギー景観のマッピングのための一般的な戦略を開発する.
主な方法:
- リラクゼーション分散型核磁共振 (NMR) スペクトロスコーピーを利用しました.
- 変化する温度でNMR実験を行った.
- FynチロシンキナーゼSH3ドメインの特定の変異変異に方法論を適用した.
主要な成果:
- 2つのSH3ドメインの変異体に対して,展開状態と折りたたみ状態の均衡状態にある低集団の折りたたみ中間体を成功裏に特定しました.
- タンパク質の折り畳みプロセスの運動学とエネルギー学を特徴づけた.
- 特定された折りたたみの中間材料の構造情報を取得しました.
結論:
- リラクゼーション分散型NMRは,一時的な,低集団のタンパク質折り畳みの中間物質の識別と特徴付けに有効です.
- この研究は,中間物質を分析することによって,タンパク質エネルギー景観を実験的に決定するための枠組みを提供します.
- タンパク質の折り畳み中間物質を理解することは,タンパク質の構造獲得と機能を理解する鍵です.
関連する概念動画
¹H NMR: Complex Splitting
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.
¹³C NMR: ¹H–¹³C Decoupling
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
Fibrous Proteins
Fibrous proteins are either long and narrow proteins or assemble to form long and thin structures. They contain repetitive units and usually consist of either alpha helices or beta sheets and, in rare cases, a mix of both. The amino acids in the primary structure often consist of repeating amino acid sequences. The role of fibrous proteins is primarily structural. Many are located in the extracellular matrix and are present in connective tissues to impart strength and joint mobility. They are...
Other Nuclides: 31P, 19F, 15N NMR
Many organic, inorganic, and biological molecules contain spin-half nuclei such as nitrogen-15, fluorine-19, and phosphorus-31. As a result, NMR studies of these nuclei have found extensive applications in chemical and biological research.
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...


