A twin-track approach has optimized proton and hydride transfer by dynamically coupled tunneling during the evolution of protochlorophyllide oxidoreductase.

ABSTRACT: Protein dynamics are crucial for realizing the catalytic power of enzymes, but how enzymes have evolved to achieve catalysis is unknown. The light-activated enzyme protochlorophyllide oxidoreductase (POR) catalyzes sequential hydride and proton transfers in the photoexcited and ground states, respectively, and is an excellent system for relating the effects of motions to catalysis. Here, we have used the temperature dependence of isotope effects and solvent viscosity measurements to analyze the dynamics coupled to the hydride and proton transfer steps in three cyanobacterial PORs and a related plant enzyme. We have related the dynamic profiles of each enzyme to their evolutionary origin. Motions coupled to light-driven hydride transfer are conserved across all POR enzymes, but those linked

SUBMITTER: Heyes DJ 

PROVIDER: S-EPMC3064235 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature