Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.
Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
Nat Commun. 2014 Dec 17;5:5737. doi: 10.1038/ncomms6737.
The temperature-jump technique, in which the sample is rapidly heated by a powerful laser pulse, has been widely used to probe the fast dynamics of folding of proteins and nucleic acids. However, the existing temperature-jump setups tend to involve sophisticated and expensive instrumentation, while providing only modest temperature changes of ~10-15 °C, and the temperature changes are only rapid for heating, but not cooling. Here we present a setup comprising a thermally conductive sapphire substrate with light-absorptive nano-coating, a microfluidic device and a rapidly switched moderate-power infrared laser with the laser beam focused on the nano-coating, enabling heating and cooling of aqueous solutions by ~50 °C on a 1-μs time scale. The setup is used to probe folding and unfolding dynamics of DNA hairpins after direct and inverse temperature jumps, revealing low-pass filter behaviour during periodic temperature variations.
温度跃变技术通过强大的激光脉冲使样品迅速升温，已被广泛用于探测蛋白质和核酸折叠的快速动力学。然而，现有的温度跃变装置往往涉及复杂和昂贵的仪器，只能提供10-15°C 的适度温度变化，并且温度变化仅在加热时迅速，而在冷却时则不然。在这里，我们提出了一种包括具有光吸收纳米涂层的导热蓝宝石衬底、微流控装置和快速切换的中功率红外激光器的装置，激光束聚焦在纳米涂层上，能够在 1μs 的时间尺度内将水溶液加热和冷却50°C。该装置用于在直接和反向温度跃变后探测 DNA 发夹的折叠和解折叠动力学，揭示了在周期性温度变化过程中的低通滤波器行为。
