物理学の研究者たちが、野心的な目標に少しずつ近づいている Physics researchers inch closer to an ambitious goal
2023-03-15 カリフォルニア大学サンタバーバラ校(UCSB)
タンパク質がどのように働くかを見るには、光パルスを使ってトリガーを起動し、タンパク質の2箇所にタグを付け、そのタグ間の距離を追跡する必要がある。研究者たちは、アイオンであるガドリニウムを使用して、そのタグの位置を測定し、その運動を観測できるようにした。
この方法を応用することで、タンパク質が特定の目的のためにデザインされるのを導くことができると考えている。
＜関連情報＞
- https://www.news.ucsb.edu/2023/020870/filming-proteins-motion
- https://onlinelibrary.wiley.com/doi/10.1002/anie.202212832
強磁場下での時間分解電子常磁性共鳴によるAsLOV2のトリガー機能ダイナミックス Triggered Functional Dynamics of AsLOV2 by Time-Resolved Electron Paramagnetic Resonance at High Magnetic Fields
Shiny Maity, Brad D. Price, C. Blake Wilson, Arnab Mukherjee, Matthieu Starck, David Parker, Maxwell Z. Wilson, Janet E. Lovett, Songi Han, Mark S. Sherwin
Angewandte Chemie International Edition Published: 13 January 2023
DOI:https://doi.org/10.1002/anie.202212832
Graphical Abstract
We took advantage of site-directed spin labeling of Gd-sTPATCN to track qualitative mechanical movement in the protein AsLOV2. Experiments were done in vitro at room temperature, allowing us to elucidate mutation-induced inhibited refolding of the Jα-helix.
Abstract
We present time-resolved Gd−Gd electron paramagnetic resonance (TiGGER) at 240 GHz for tracking inter-residue distances during a protein’s mechanical cycle in the solution state. TiGGER makes use of Gd-sTPATCN spin labels, whose favorable qualities include a spin-7/2 EPR-active center, short linker, narrow intrinsic linewidth, and virtually no anisotropy at high fields (8.6 T) when compared to nitroxide spin labels. Using TiGGER, we determined that upon light activation, the C-terminus and N-terminus of AsLOV2 separate in less than 1 s and relax back to equilibrium with a time constant of approximately 60 s. TiGGER revealed that the light-activated long-range mechanical motion is slowed in the Q513A variant of AsLOV2 and is correlated to the similarly slowed relaxation of the optically excited chromophore as described in recent literature. TiGGER has the potential to valuably complement existing methods for the study of triggered functional dynamics in proteins.
