1. Acceleration of catalysis in dihydrofolate reductase by transient, site-specific photothermal excitation.
- Author
-
Kozlowski R, Zhao J, and Dyer RB
- Subjects
- Catalysis, Catalytic Domain radiation effects, Gold chemistry, Heating adverse effects, Kinetics, Metal Nanoparticles radiation effects, Protein Conformation radiation effects, Tetrahydrofolate Dehydrogenase ultrastructure, Metal Nanoparticles chemistry, Models, Molecular, Tetrahydrofolate Dehydrogenase chemistry
- Abstract
We have studied the role of protein dynamics in chemical catalysis in the enzyme dihydrofolate reductase (DHFR), using a pump-probe method that employs pulsed-laser photothermal heating of a gold nanoparticle (AuNP) to directly excite a local region of the protein structure and transient absorbance to probe the effect on enzyme activity. Enzyme activity is accelerated by pulsed-laser excitation when the AuNP is attached close to a network of coupled motions in DHFR (on the FG loop, containing residues 116-132, or on a nearby alpha helix). No rate acceleration is observed when the AuNP is attached away from the network (distal mutant and His-tagged mutant) with pulsed excitation, or for any attachment site with continuous wave excitation. We interpret these results within an energy landscape model in which transient, site-specific addition of energy to the enzyme speeds up the search for reactive conformations by activating motions that facilitate this search., Competing Interests: The authors declare no competing interest.
- Published
- 2021
- Full Text
- View/download PDF