Temperature-dependent Surface Plasmon Resonance Research Articles

The temperature impact on the characteristics of the surface plasmon resonance sensors element

Characteristics of the sensor based on surface plasmon resonance under temperature impact have been theoretically analyzed. The theoretical analysis of the temperature impact involves the thermo-optic effect; phonon – electron scattering and electron – electron scattering in the metal layer. The two different metals (silver and gold) have been used for research characteristics surface plasmon resonance sensor element. Temperature dependences of the resonance position of the surface plasmon resonance reflectance of the prism-based structure were calculated. This detailed analysis of temperature dependent surface plasmon resonance and sensitivity is directed to obtain the best possible implementation of the sensor resistant to the temperature change.

General method for kinetic and thermodynamic evaluation of a receptor model peptide-drug molecule interaction studied by surface plasmon resonance

This work presents a detailed description of a commonly used and low-cost evaluation process that is simply based on the nonlinear fitting of concentration-, time- and temperature-dependent surface plasmon resonance (SPR) sensorgrams in order to provide kinetic and thermodynamic characterization of a biologically relevant interaction. Regardless of type, this evaluation proceeding is maximally suitable to manage the time-dependent sensor signals of other quasi two-dimensional sensor techniques, like quartz crystal microbalance (QCM) or optical waveguide lightmode spectroscopy (OWLS). Based on the hypothetic reaction schemes, the SPR signals have been fitted by the analytical solutions of the rate equations using optional spreadsheet software. Statistical tests of the goodness of nonlinear fits confirm the application of a reversible, pseudo first order kinetic model, in this way the apparent (kobs), the association (ka) and the dissociation (kd) constants as well as the equilibrium constants (KA) and the Gibbs free energy change (ΔG) have been calculated at six different temperatures. The enthalpy (ΔH0), entropy (ΔS0) and heat capacity changes (ΔCp) have also been estimated using nonlinear regression analysis. The sign and values of the state functions approve the presence of a salt bridge between a model polypeptide fragment of human glutamate receptor (ANYT) and kynurenic acid (KYNA) which was confirmed by molecular docking calculations as well.

Thermodynamics and kinetics of RNA tertiary structure formation in the junctionless hairpin ribozyme

The hairpin ribozyme consists of two RNA internal loops that interact to form the catalytically active structure. This docking transition is a rare example of intermolecular formation of RNA tertiary structure without coupling to helix annealing. We have used temperature-dependent surface plasmon resonance (SPR) to characterize the thermodynamics and kinetics of RNA tertiary structure formation for the junctionless form of the ribozyme, in which loops A and B reside on separate molecules. We find docking to be strongly enthalpy-driven and to be accompanied by substantial activation barriers for association and dissociation, consistent with the structural reorganization of both internal loops upon complex formation. Comparisons with the parallel analysis of a ribozyme variant carrying a 2′-O-methyl modification at the self-cleavage site and with published data in other systems reveal a surprising diversity of thermodynamic signatures, emphasizing the delicate balance of contributions to the free energy of formation of RNA tertiary structure.