Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.
Phys Rev Lett. 2024 Jan 26;132(4):048402. doi: 10.1103/PhysRevLett.132.048402.
Prior work has shown that small proteins can fold (i.e., convert from unstructured to structured states) within 10 μs. Here we use time-resolved solid state nuclear magnetic resonance (ssNMR) methods to show that full folding of the 35-residue villin headpiece subdomain (HP35) requires a slow annealing process that has not been previously detected. ^{13}C ssNMR spectra of frozen HP35 solutions, acquired with a variable time τ_{e} at 30 °C after rapid cooling from 95 °C and before rapid freezing, show changes on the 3-10 ms timescale, attributable to slow rearrangements of protein sidechains during τ_{e}.
先前的研究表明，小分子蛋白可以在 10μs 内折叠（即从不稳定状态转变为稳定状态）。在这里，我们使用时间分辨的固态核磁共振（ssNMR）方法表明，35 个残基的绒毛蛋白头部片段（HP35）的完全折叠需要一个以前未检测到的缓慢退火过程。在从 95°C 快速冷却到 30°C 后并在快速冷冻之前，通过在 30°C 下用可变时间 τ_e 获得的冷冻 HP35 溶液的 13C ssNMR 谱在 3-10ms 时间尺度上显示出变化，这归因于 τ_e 期间蛋白质侧链的缓慢重排。
