Unveiling the Photoactivation Mechanism of BLUF Photoreceptor Protein through Hybrid Quantum Mechanics/Molecular Mechanics Free-Energy Calculation.

ABSTRACT: OaPAC is a photoactivated enzyme that forms a homodimer. The two blue-light using flavin (BLUF) photoreceptor domains are connected to the catalytic domains with long coiled-coil C-terminal helices. Upon photoreception, reorganization of the hydrogen bonding network between Tyr6, Gln48, and the chromophore in the BLUF domain and keto-enol tautomerization of Gln48 are thought to occur. However, the quantitative energetics of the photoisomerization reaction and how the BLUF domain's structural change propagates toward the catalytic domain are still unknown. We evaluate the free-energy differences among the dark-state and two different light-state structures by the free-energy perturbation calculations combined with QM/MM free-energy optimizations. Furthermore, we performed long-time MD simul

SUBMITTER: Taguchi M 

PROVIDER: S-EPMC11613238 | biostudies-literature | 2024 Nov

REPOSITORIES: biostudies-literature