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We report a method for the structure-based calculation of the spectral density of the pigment-protein coupling in light-harvesting complexes that combines normal-mode analysis with the charge density coupling (CDC) and transition charge from electrostatic potential (TrEsp) methods for the computation of site energies and excitonic couplings, respectively.(More)
The linear optical spectra (absorbance, linear dichroism, circular dichroism, fluorescence) of the CP43 (PsbC) antenna of the photosystem II core complex (PSIIcc) pertaining to the S0 → S1 (QY) transitions of the chlorophyll (Chl) a pigments are simulated by applying a combined quantum chemical/electrostatic method to obtain excitonic couplings and local(More)
The experimentally obtained time-resolved fluorescence spectra of photosystem II (PS II) core complexes, purified from a thermophilic cyanobacterium Thermosynechococcus vulcanus, at 5-180 K are compared with simulations. Dynamic localization effects of excitons are treated implicitly by introducing exciton domains of strongly coupled pigments. Exciton(More)
A theory for calculating time– and frequency–domain optical spectra of pigment–protein complexes is presented using a density matrix approach. Non-Markovian effects in the exciton– vibrational coupling are included. A correlation function is deduced from the simulation of 1.6 K fluorescence line narrowing spectra of a monomer pigment–protein complex ͑B777͒,(More)
The Poisson-TrEsp method (where TrEsp stands for transition charges from electrostatic potentials) has been successfully applied to calculate excitonic couplings in a variety of pigment–protein complexes. It relies on an isomorphism that allows for relating the excitonic coupling between transition densities in dielectric media to their Coulomb coupling.(More)
Site-directed mutations were constructed in photosystem II of Synechocystis sp. PCC6803 in which the axial ligand, D1-His198, of special pair chlorophyll PD1 was replaced with Gln and where D1-Thr179, which overlies monomeric chlorophyll ChlD1, was replaced with His. The D1-His198Gln mutation produces a 3nm displacement to the blue of the bleaching minimum(More)
In Photosystem I (PS I) long-wavelength chlorophylls (LWC) of the core antenna are known to extend the spectral region up to 750 nm for absorbance of light that drives photochemistry. Here we present clear evidence that even far-red light with wavelengths beyond 800 nm, clearly outside the LWC absorption bands, can still induce photochemical charge(More)