TY  - JOUR
A1  - Lokstein, Heiko
A1  - Betke, Alexander
A1  - Krikunova, Maria
A1  - Teuchner, Klaus
A1  - Voigt, Bernd
T1  - Elucidation of structure-function relationships in plant major light-harvesting complex (LHC II) by nonlinear spectroscopy
JF  - Photosynthesis research
N2  - 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.
KW  - Excitonic interactions
KW  - Laser spectroscopy
KW  - Light-harvesting complex (LHC II)
Y1  - 2012
U6  - https://doi.org/10.1007/s11120-011-9700-y
SN  - 0166-8595
VL  - 111
IS  - 1-2
SP  - 227
EP  - 235
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Voigt, Bernd
A1  - Krikunova, Maria
A1  - Lokstein, Heiko
T1  - Influence of detergent concentration on aggregation and the spectroscopic properties of light-harvesting complex II
Y1  - 2008
U6  - https://doi.org/10.1007/s11120-007-9250-5
ER  - 
TY  - JOUR
A1  - Krikunova, Maria
A1  - Lokstein, Heiko
A1  - Leupold, Dieter
A1  - Hiller, Roger G.
A1  - Voigt, B.
T1  - Pigment-pigment interactions in PCP of Amphidinium carterae investigated by nonlinear polarization spectroscopy in the frequency domain
N2  - 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
Y1  - 2006
ER  -