Anunciado Divina B, Nyugen Vyncent P, Hurst Gregory B, Doktycz Mitchel J, Urban Volker, Langan Paul, Mamontov Eugene, O'Neill Hugh
Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States.
J Phys Chem Lett. 2017 Apr 20;8(8):1899-1904. doi: 10.1021/acs.jpclett.7b00399. Epub 2017 Apr 13.
Selectively labeled GroEL protein was produced in living deuterated bacterial cells to enhance its neutron scattering signal above that of the intracellular milieu. Quasi-elastic neutron scattering shows that the in-cell diffusion coefficient of GroEL was (4.7 ± 0.3) × 10 m/s, a factor of 4 slower than its diffusion coefficient in buffer solution. Internal protein dynamics showed a relaxation time of (65 ± 6) ps, a factor of 2 slower compared to the protein in solution. Comparison to the literature suggests that the effective diffusivity of proteins depends on the length and time scale being probed. Retardation of in-cell diffusion compared to the buffer becomes more significant with the increasing probe length scale, suggesting that intracellular diffusion of biomolecules is nonuniform over the cellular volume. The approach outlined here enables investigation of protein dynamics within living cells to open up new lines of research using "in-cell neutron scattering" to study the dynamics of complex biomolecular systems.
在活的氘代细菌细胞中产生选择性标记的GroEL蛋白，以增强其在细胞内环境之上的中子散射信号。准弹性中子散射表明，GroEL在细胞内的扩散系数为(4.7±0.3)×10 m/s，比其在缓冲溶液中的扩散系数慢4倍。内部蛋白质动力学显示弛豫时间为(65±6) ps，比溶液中的蛋白质慢2倍。与文献的比较表明，蛋白质的有效扩散率取决于所探测的长度和时间尺度。与缓冲液相比，随着探测长度尺度的增加，细胞内扩散的延迟变得更加显著，这表明生物分子在细胞体积内的扩散是不均匀的。这里概述的方法能够研究活细胞内的蛋白质动力学，从而开辟新的研究方向，利用“细胞内中子散射”来研究复杂生物分子系统的动力学。
