Significant Impact of Deprotonated Status on the Photoisomerization Dynamics of Bacteriophytochrome Chromophore

Abstract

We report that the photoinduced dynamics of the phytochrome chromophore is strongly dependent on the protonation/deprotonation states of the pyrrole ring. The on-the-fly surface hopping dynamics simulations were performed to study the photoisomerization of different protonation/deprotonation phytochrome chromophore models. The simulation results indicate that the deprotonations at the pyrrole rings significantly modify the photoinduced nonadiabatic dynamics, leading to distinctive population decay dynamics and different reaction channels. Such feature can be well explained by the formation of the different hydrogen bond network patterns. Therefore, the proper understanding of the photoisomerization mechanism of phytochrome chromophore must take the hydrogen bond network into account. This work provides the new insights into the photobiological functions of phytochrome chromophore and suggests the possible ideas to control of its photoconversion processes for further rational engineering in optical applications.

The impact of different geometrical restrictions on the nonadiabatic photoisomerization of biliverdin chromophores

“…In addition, the hydrogen-bond network patterns greatly affect the photoisomerization channels of central chromophores, when a different deprotonation status exists in these pyrrole rings. 35,36 These works demonstrated that the photoisomerization of phytochrome chromophores may be adjusted by the distinctive confinement of chromophores in the vacuum and in the surrounding environment. In a vacuum, the chromophore is a ''free'' molecule and the rotation of any carbon-carbon bond is not affected by external factors.…”

Photoisomerization of phytochrome chromophore models: an XMS-CASPT2 study

“…18 Such an active space size is computationally intractable since the maximum size currently achievable is 18 electrons in 18 orbitals. 19 Therefore, in previous studies a compromise was chosen to either employ approximate electronic structure methods, such as a semi-empirical method, [20][21][22] or to truncate the chromophore. [23][24][25][26][27][28] In the latter approach, typically, the propionic acid groups 23,29 are replaced by hydrogen atoms because they are not part of the conjugated psystem.…”

The Impact of the Different Geometrical Restrictions on the Nonadiabatic Photoisomerization of Biliverdin Chromophore

“…In addition, the hydrogen-bond network patterns greatly affect the photoisomerization channels of central chromophores, when different deprotonation status exist in these pyrrole rings. 33,34 These works demonstrated that the photoisomerization of phytochrome chromophores may be adjusted by the distinctive confinement of chromophores in the vacuum and in the surrounding environment. In a vacuum, the chromophore is a "free" molecule and the rotation of any carbon-carbon bond is not affected by external factors.…”