Anisotropic circular dichroism of light-harvesting complex II in oriented lipid bilayers: Theory meets experiment

DOI: 10.1021/acs.jpcb.8b12474

Authors: Parveen Akhtar (Hungarian Academy of Sciences; ELI-HU Nonprofit Kft.) , Dominik Lindorfer (Johannes Kepler University Linz) , Monika Lingvay (Hungarian Academy of Sciences) , Krzysztof Pawlak (Hungarian Academy of Sciences) , Otto Zsiros (Hungarian Academy of Sciences) , Giuliano Siligardi (Diamond Light Source) , Tamas Javorfi (Diamond Light Source) , Márta Dorogi (Hungarian Academy of Sciences) , Bettina Ughy (Hungarian Academy of Sciences) , Gyozo Garab (Hungarian Academy of Sciences; University of Ostrava) , Thomas Renger (Johannes Kepler University Linz) , Petar H. Lambrev (Hungarian Academy of Sciences)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Journal Of Physical Chemistry B

State: Published (Approved)
Published: January 2019
Diamond Proposal Number(s): 15094 , 16232 , 17698 , 19120 , 20644

Abstract: Anisotropic circular dichroism (ACD) spectroscopy of macroscopically aligned molecules reveals additional information about their excited states that is lost in the CD of randomly-oriented solutions. ACD spectra of light-harvesting complex II (LHCII)—the main peripheral antenna of photosystem II in plants—in oriented lipid bilayers, were recorded from the far-UV to the visible wavelength region. The ACD spectra show a drastically enhanced magnitude and level of detail compared to the isotropic CD spectra, resolving a greater number of bands and weak optical transitions. Exciton calculations show that the spectral features in the chlorophyll Qy region are well reproduced by an existing Hamiltonian for LHCII, providing further evidence for the identity of energy sinks at chlorophylls a603 and a610 in the stromal layer and chlorophylls a604 and a613 in the luminal layer. We propose ACD spectroscopy to be a valuable tool linking the three-dimensional structure and the photophysical properties of pigment–protein complexes.

Journal Keywords: photosynthetic complexes; model membranes; optical spectroscopy; excitonic CD; exciton theory; oriented CD

Subject Areas: Chemistry


Instruments: B23-Circular Dichroism