Effect of viscogens on the kinetic response of a photoperturbed allosteric protein
Copyright policy )Effect of viscogens on the kinetic response of a photoperturbed allosteric protein
By covalently binding a photoswitchable linker across the binding groove of the PDZ2 domain, a small conformational change can be photo-initiated that mimics the allosteric transition of the protein. The response of its binding groove is investigated with the help of ultrafast pump-probe IR spectroscopy from picoseconds to tens of microseconds. The temperature dependence of that response is compatible with diffusive dynamics on a rugged energy landscape without any prominent energy barrier. Furthermore, the dependence of the kinetics on the concentration of certain viscogens, sucrose, and glycerol, has been investigated. A pronounced viscosity dependence is observed that can be best fit by a power law, i.e., a fractional viscosity dependence. The change of kinetics when comparing sucrose with glycerol as viscogen, however, provides strong evidence that direct interactions of the viscogen molecule with the protein do play a role as well. This conclusion is supported by accompanying molecular dynamics simulations.
- University of Zurich Switzerland
10120 Department of Chemistry, Glycerol, Protein Folding, Sucrose, Light, Viscosity, Protein Tyrosine Phosphatase, Non-Receptor Type 13, PDZ Domains, Molecular Dynamics Simulation, Photochemical Processes, 3100 General Physics and Astronomy, Kinetics, 540 Chemistry, Humans, 1606 Physical and Theoretical Chemistry
10120 Department of Chemistry, Glycerol, Protein Folding, Sucrose, Light, Viscosity, Protein Tyrosine Phosphatase, Non-Receptor Type 13, PDZ Domains, Molecular Dynamics Simulation, Photochemical Processes, 3100 General Physics and Astronomy, Kinetics, 540 Chemistry, Humans, 1606 Physical and Theoretical Chemistry
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