An Optics-Based Variable-Temperature Assay System For Characterizing Thermodynamics Of Biomolecular Reactions On Solid Support

A biological state is equilibrium of multiple concurrent biomolecular reactions. The relative importance of these reactions depends on physiological temperature typically between 10 degrees C and 50 degrees C. Experimentally the temperature dependence of binding reaction constants reveals thermodynamics and thus details of these biomolecular processes. We developed a variable-temperature opto-fluidic system for real-time measurement of multiple (400-10000) biomolecular binding reactions on solid supports from 10 degrees C to 60 degrees C within +/- 0.1 degrees C. We illustrate the performance of this system with investigation of binding reactions of plant lectins (carbohydrate-binding proteins) with 24 synthetic glycans (i.e., carbohydrates). We found that the lectin-glycan reactions in general can be enthalpy-driven, entropy-driven, or both, and water molecules play critical roles in the thermodynamics of these reactions. (C) 2013 AIP Publishing LLC.