How orange carotenoid protein controls the excited state dynamics of canthaxanthin

Arcidiacono, Amanda; Accomasso, Davide; Cupellini, Lorenzo; Mennucci, Benedetta

doi:10.1039/d3sc02662k

Cited by 13 publications

(7 citation statements)

References 62 publications

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“…The QM adiabatic electronic energies of carotenoids were computed using a SE configuration interaction (CI) approach, which proved to be effective in the description of their low-lying excited states. − , This method performs a CI calculation within an active space. The targets E normalb normalr normali normalg normalh normalt and E normald normala normalr normalk used to train the ML models were obtained by performing our diabatization strategy.…”

Section: Methodsmentioning

confidence: 99%

“…Nevertheless, for our purposes, it proved to be more efficient than other, more general, diabatization strategies. For example, a diabatization based on the maximization of the overlap matrix with reference states was used for carotenoids in various previous works by some of us, − but it is less efficient when applied to geometries that are very different from the one used as a reference . Another issue generally regarding property-unblending strategies, like the one employed here, is that the sign of the diabatic couplings (off-diagonal elements of D ) is arbitrary and can be inconsistent from geometry to geometry.…”

Section: Methodsmentioning

confidence: 99%

“…Quantum chemical and multiscale calculations have been extremely useful to understand the excited-state properties of carotenoids in various environments. − In particular, some of the present authors demonstrated that a quantum mechanics/molecular mechanics (QM/MM) approach combining multireference semiempirical (SE) methods with electrostatic embedding of the environment is able to capture both the dark and the bright states of carotenoids. − …”

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

Predicting Solvatochromism of Chromophores in Proteins through QM/MM and Machine Learning

Arcidiacono,

Cignoni,

Mazzeo

et al. 2024

J. Phys. Chem. A

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Solvatochromism occurs in both homogeneous solvents and more complex biological environments, such as proteins. While in both cases the solvatochromic effects report on the surroundings of the chromophore, their interpretation in proteins becomes more complicated not only because of structural effects induced by the protein pocket but also because the protein environment is highly anisotropic. This is particularly evident for highly conjugated and flexible molecules such as carotenoids, whose excitation energy is strongly dependent on both the geometry and the electrostatics of the environment. Here, we introduce a machine learning (ML) strategy trained on quantum mechanics/molecular mechanics calculations of geometrical and electrochromic contributions to carotenoids' excitation energies. We employ this strategy to compare solvatochromism in protein and solvent environments. Despite the important specifities of the protein, ML models trained on solvents can faithfully predict excitation energies in the protein environment, demonstrating the robustness of the chosen descriptors.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Predicting Solvatochromism of Chromophores in Proteins through QM/MM and Machine Learning

Arcidiacono,

Cignoni,

Mazzeo

et al. 2024

J. Phys. Chem. A

Self Cite

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“…To better characterize the nature of the electronic states during the ultrafast dynamics, we employ a diabatic representation in the same way as reported in our previous works. [24,25] More specifically, the diabatic states are defined so that they maximally resemble the lowest adiabatic singlet states of lutein (S 0 -S 3 ) at its S 0 minimum geometry, and are indicated using their (pseudo)symmetry, i.e., 1Ag − , 2Ag − , 1B + u , and 1B − u (more details are provided in Section 2.2). Figure 3b displays the diabatic state population dynamics for L1-Lut (left panel) and L2-Lut (right panel).…”

Section: Ultrafast Decay Pathway Of the S2 State Of Lutein: L1 Vs L2mentioning

confidence: 99%

“…[24] Furthermore, some of us have recently extended the application of the same methodology to the excited state dynamics of another carotenoid (canthaxanthin) in the Orange Carotenoid Protein (OCP). [25] Strikingly, these investigations suggested that the dark state S x is equally involved in the ultrafast decay pathway of the S 2 state of the two different carotenoids.…”

Section: Introductionmentioning

confidence: 98%

Ultrafast Excited-State Dynamics of Luteins in the major light-harvesting complex LHCII

Pedraza González,

Accomasso,

Cupellini

et al. 2023

Preprint

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Carotenoid pigments are known to present a functional versatility when bound to light-harvesting complexes. This versatility originates from a strong correlation between a complex electronic structure and a flexible geometry which is easily tunable by the surrounding protein environment. Here, we investigated how the different L1 and L2 sites of the major trimeric light-harvesting complex (LHCII) of green plants tune the electronic structure of the two embedded luteins, and how this reflects on their ultrafast dynamics upon excitation. By combining molecular dynamics and quantum mechanics/molecular mechanics calculations, we found that the two luteins feature a different conformation around the second dihedral angle in the lumenal side. The s-cis preference of the lutein in site L2 allows for a more planar geometry of the π-conjugated backbone, which results in an increased degree of delocalization and a reduced excitation energy, explaining the experimentally observed red shift. Despite these remarkable differences, according to surface hopping simulations the two luteins present analogous ultrafast dynamics upon excitation: the bright S2 state quickly decays (in ∼50 fs) to the dark intermediate Sx, eventually ending up in the S1 state. Furthermore, by employing two different theoretical approaches (i.e., Förster theory and an excitonic version of surface hopping), we investigated the experimentally debated energy transfer between the two luteins. With both approaches, no evident energy transfer was observed in the ultrafast timescale

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Quantum‐Classical Simulations Reveal the Photoisomerization Mechanism of a Prototypical First‐Generation Molecular Motor

Accomasso,

Jankowska

2024

Chemistry A European J

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Light‐driven molecular rotary motors convert the energy of absorbed light into unidirectional rotational motion and are key components in the design of molecular machines. The archetypal class of light‐driven rotary motors is chiral overcrowded alkenes, where the rotational movement is achieved through consecutive cis‐trans photoisomerization reactions and thermal helix inversion steps. While the thermal steps have been rather well understood by now, our understanding of the photoisomerization reactions of overcrowded alkene‐based motors still misses key points that would explain the striking differences in operation efficiency of the known systems. Here, we employ quantum‐chemical calculations and nonadiabatic molecular dynamics simulations to investigate the excited‐state decay and photoisomerization mechanism in a prototypical alkene‐based first‐generation rotary motor. We show that the initially excited bright state undergoes an ultrafast relaxation to multiple excited‐ state minima separated by low energy barriers and reveal a slow picosecond‐timescale decay to the ground state, which only occurs from a largely twisted dark excited‐state minimum, far from any conical‐intersection point. Additionally, we attribute the origin of the high yields of forward photoisomerization in our investigated motor to the favorable topography of the ground‐state potential energy surface, which is controlled by the conformation of the central cyclopentene rings.

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How orange carotenoid protein controls the excited state dynamics of canthaxanthin

Abstract: Orange Carotenoid Protein (OCP) is a ketocarotenoid-binding protein essential for photoprotec- tion in cyanobacteria. The main steps of the photoactivated conversion which converts OCP from its resting state to the...

Cited by 13 publications

References 62 publications

Predicting Solvatochromism of Chromophores in Proteins through QM/MM and Machine Learning

Predicting Solvatochromism of Chromophores in Proteins through QM/MM and Machine Learning

Ultrafast Excited-State Dynamics of Luteins in the major light-harvesting complex LHCII

Quantum‐Classical Simulations Reveal the Photoisomerization Mechanism of a Prototypical First‐Generation Molecular Motor

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