For the Chl-a molecules, the QM region was reduced by truncating the phytyl tail at the so-called C1-C2 bond and caped with a hydrogen atom. The rest of the phytyl tail has been described as part of the MM environment together with the protein, solvent, ions and the other pigments. This kind of QM/MM setup was employed successfully earlier for BChl-a and Chl-a/b molecules of bacterial and plant LH systems in order to reduce the computational cost . Furthermore, as the Chl-c pigments do not contain phytyl tails, for these molecules the whole chromophore was considered as the QM region while the rest of the system was described by MM point charges. For the semi-empirical methods, we have considered the ZINDO/S-CIS and the TD-LC-DFTB level of theories. In ZINDO/S-CIS calculations, the 10 HOMOs and the 10 LUMOs have been considered for the active space. Subsequently, excited state calculations have been carried out using the time-dependent extension of the long-range corrected DFTB (TD-LC-DFTB) employing the OB2 parameter set . As alternatives for the excited state calculations, we have furthermore employed the semi-empirical ZINDO/S-CIS method (Zerner's intermediate neglect of differential orbital method with spectroscopic parameters together with configuration interaction using single excitation) and higher level QM methods like the time-dependent long-range corrected DFT (TD-DFT using the CAM-B3LYP and the ωB97X functionals ) and the DFT/MRCI approach . Using individual structures has the advantage that one can test various highlevel QM methods. The TD-LC-DFT calculations were performed based on the CAM-B3LYP and the ωB97X range-separated functionals together with the Def2-TZVP basis set.