title: Ultrafast cooling reveals microsecond-scale biomolecular dynamics.
abstract: 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.
authors.affiliation: Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Polinkovsky
authors.affiliation: Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: Yann
authors.initials: Y
authors.lastname: Gambin
authors.affiliation: Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: Priya R
authors.initials: PR
authors.lastname: Banerjee
authors.affiliation: Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Erickstad
authors.affiliation: Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Groisman
authors.affiliation: Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: Ashok A
authors.initials: AA
authors.lastname: Deniz
mesh_terms: D003080:Cold Temperature; D004247:DNA / Q000737:chemistry*; D006358:Hot Temperature; D055029:Inverted Repeat Sequences; D007700:Kinetics; D007834:Lasers; D008027:Light; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D056004:Molecular Dynamics Simulation; D009690:Nucleic Acid Conformation; D013997:Time Factors
chemical_list: D004247:DNA