@misc{LoksteinKrikunovaTeuchneretal.2011,
  author    = {Lokstein, Heiko and Krikunova, Maria and Teuchner, Klaus and Voigt, Bernd},
  title     = {Elucidation of structure-function relationships in photosynthetic light-harvesting antenna complexes by non-linear polarization spectroscopy in the frequency domain (NLPF)},
  series = {Journal of plant physiology : biochemistry, physiology, molecular biology and biotechnology of plants},
  volume    = {168},
  journal   = {Journal of plant physiology : biochemistry, physiology, molecular biology and biotechnology of plants},
  number    = {12},
  publisher = {Elsevier},
  address   = {Jena},
  issn      = {0176-1617},
  doi       = {10.1016/j.jplph.2010.12.012},
  pages     = {1488 -- 1496},
  year      = {2011},
  abstract  = {Photosynthetically active pigments are usually organized into pigment-protein complexes. These include light-harvesting antenna complexes (LHCs) and reaction centers. Site energies of the bound pigments are determined by interactions with their environment, i.e., by pigment-protein as well as pigment-pigment interactions. Thus, resolution of spectral substructures of the pigment-protein complexes may provide valuable insight into structure-function relationships. By means of conventional (linear) and time-resolved spectroscopic techniques, however, it is often difficult to resolve the spectral substructures of complex pigment-protein assemblies. Nonlinear polarization spectroscopy in the frequency domain (NLPF) is shown to be a valuable technique in this regard. Based on initial experimental work with purple bacterial antenna complexes as well as model systems NLPF has been extended to analyse the substructure(s) of very complex spectra, including analyses of interactions between chlorophylls and "optically dark" states of carotenoids in LHCs. The paper reviews previous work and outlines perspectives regarding the application of NLPF spectroscopy to disentangle structure-function relationships in pigment-protein complexes.},
  language  = {en}
}
@misc{LoksteinBetkeKrikunovaetal.2012,
  author    = {Lokstein, Heiko and Betke, Alexander and Krikunova, Maria and Teuchner, Klaus and Voigt, Bernd},
  title     = {Elucidation of structure-function relationships in plant major light-harvesting complex (LHC II) by nonlinear spectroscopy},
  series = {Photosynthesis research},
  volume    = {111},
  journal   = {Photosynthesis research},
  number    = {1-2},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {0166-8595},
  doi       = {10.1007/s11120-011-9700-y},
  pages     = {227 -- 235},
  year      = {2012},
  abstract  = {Conventional linear and time-resolved spectroscopic techniques are often not appropriate to elucidate specific pigment-pigment interactions in light-harvesting pigment-protein complexes (LHCs). Nonlinear (laser-) spectroscopic techniques, including nonlinear polarization spectroscopy in the frequency domain (NLPF) as well as step-wise (resonant) and simultaneous (non-resonant) two-photon excitation spectroscopies may be advantageous in this regard. Nonlinear spectroscopies have been used to elucidate substructure(s) of very complex spectra, including analyses of strong excitonic couplings between chlorophylls and of interactions between (bacterio) chlorophylls and "optically dark'' states of carotenoids in LHCs, including the major antenna complex of higher plants, LHC II. This article shortly reviews our previous study and outlines perspectives regarding the application of selected nonlinear laser-spectroscopic techniques to disentangle structure-function relationships in LHCs and other pigment-protein complexes.},
  language  = {en}
}
@article{VoigtKrikunovaLokstein2008,
  author    = {Voigt, Bernd and Krikunova, Maria and Lokstein, Heiko},
  title     = {Influence of detergent concentration on aggregation and the spectroscopic properties of light-harvesting complex II},
  doi       = {10.1007/s11120-007-9250-5},
  year      = {2008},
  language  = {en}
}
@article{KrikunovaLoksteinLeupoldetal.2006,
  author    = {Krikunova, Maria and Lokstein, Heiko and Leupold, Dieter and Hiller, Roger G. and Voigt, B.},
  title     = {Pigment-pigment interactions in PCP of Amphidinium carterae investigated by nonlinear polarization spectroscopy in the frequency domain},
  year      = {2006},
  abstract  = {Peridinin-chlorophyll a-protein (PCP) is a unique antenna complex in dinoflagellates that employs peridinin (a carotenoid) as its main light-harvesting pigment. Strong excitonic interactions between peridinins, as well as between peridinins and chlorophylls (Chls) a, can be expected from the short intermolecular distances revealed by the crystal structure. Different experimental approaches of nonlinear polarization spectroscopy in the frequency domain (NLPF) were used to investigate the various interactions between pigments in PCP of Amphidinium carterae at room temperature. Lineshapes of NLPF spectra indicate strong excitonic interactions between the peridinin's optically allowed S-2 (1Bu(+)) states. A comprehensive subband analysis of the distinct NLPF spectral substructure in the peridinin region allows us to assign peridinin subbands to the two Chls a in PCP having different S-1-state lifetimes. Peridinin subbands at 487, 501, and 535 nm were assigned to the longer-lived Chl, whereas a peridinin subband peaking at 515 nm was detected in both clusters. Certain peridinin(s), obviously corresponding to the subband centered at 487 nm, show(s) specific (possibly Coulombic?) interaction between the optically dark S-1(2A(g)(-)) and/or intramolecular charge- transfer (ICT) state and S-1 of Chl a. The NLPF spectrum, hence, indicates that this peridinin state is approximately isoenergetic or slightly above S-1 of Chl a. A global subband analysis of absorption and NLPF spectra reveals that the Chl a Q(y)-band consists of two subbands ( peaking at 669 and 675 nm and having different lifetimes), confirmed by NLPF spectra recorded at high pump intensities. At the highest applied pump intensities an additional band centered at <= 660 nm appears, suggesting-together with the above results-an assignment to a low-dipole moment S-0-> S-1/ICT transition of peridinin},
  language  = {en}
}