Share Email Print
cover

Proceedings Paper • Open Access

Photophysics in single light-harvesting complexes II: from micelle to native nanodisks
Author(s): J. Michael Gruber; Stefan Scheidelaar; Henny van Roon; Jan P. Dekker; J. Antoinette Killian; Rienk van Grondelle

Paper Abstract

Most photosynthetic pigment-protein complexes of algae and higher plants are integral membrane proteins and are thus usually isolated in the presence of detergent to provide a hydrophobic interface and prevent aggregation. It was recently shown that the styrene maleic acid (SMA) copolymer can be used instead to solubilize and isolate protein complexes with their native lipid environment into nanodisk particles. We isolated LHCII complexes in SMA and compared their photophysics with trimeric LHCII complexes in β-DM detergent micelles to understand the effect of the native environment on the function of light-harvesting antennae. The triplet state kinetics and the calculated relative absorption cross section of single complexes indicate the successful isolation of trimeric complexes in SMA nanodisks, confirming the trimeric structure as the likely native configuration. The survival time of complexes before they photobleach is increased in SMA compared to detergent which might be explained by a stabilizing effect of the co-purified lipids in nanodisks. We furthermore find an unquenched fluorescence lifetime of 3.5 ns for LHCII in SMA nanodisks which coincides with detergent isolated complexes and notably differs from 2 ns typically found in native thylakoid structures. A large dynamic range of partially quenched complexes both in detergent micelles and lipid nanodisks is demonstrated by correlating the fluorescence lifetime with the intensity and likely reflects the conformational freedom of these complexes. This further supports the hypothesis that fluorescence intermittency is an intrinsic property of LHCII that may be involved in excess energy dissipation in native light-harvesting.

Paper Details

Date Published: 1 March 2016
PDF: 10 pages
Proc. SPIE 9714, Single Molecule Spectroscopy and Superresolution Imaging IX, 97140A (1 March 2016); doi: 10.1117/12.2211588
Show Author Affiliations
J. Michael Gruber, VU Univ. Amsterdam (Netherlands)
Stefan Scheidelaar, Utrecht Univ. (Netherlands)
Henny van Roon, VU Univ. Amsterdam (Netherlands)
Jan P. Dekker, VU Univ. Amsterdam (Netherlands)
J. Antoinette Killian, Utrecht Univ. (Netherlands)
Rienk van Grondelle, VU Univ. Amsterdam (Netherlands)


Published in SPIE Proceedings Vol. 9714:
Single Molecule Spectroscopy and Superresolution Imaging IX
Jörg Enderlein; Ingo Gregor; Zygmunt Karol Gryczynski; Rainer Erdmann; Felix Koberling, Editor(s)

© SPIE. Terms of Use
Back to Top