Spectroscopy of individual light-harvesting 2 complexes of Rhodopseudomonas acidophila: diagonal disorder, intercomplex heterogeneity, spectral diffusion, and energy transfer in the B800 band.
This paper reports a detailed spectroscopic study of the B800 absorption band of individual light-harvesting 2 (LH2) complexes of the photosynthetic purple bacterium Rhodopseudomonas acidophila at 1. 2 K. By applying single-molecule detection techniques to this system, details and properties can be revealed that remain obscured in conventional ensemble experiments. For instance, from fluorescence-excitation spectra of the individual complexes a more direct measure of the diagonal disorder could be obtained. Further spectral diffusion phenomena and homogeneous linewidths of individual bacteriochlorophyll a (BChl a) molecules are observed, revealing valuable information on excited-state dynamics. This work demonstrates that it is possible to obtain detailed spectral information on individual pigment-protein complexes, providing direct insight into their electronic structure and into the mechanisms underlying the highly efficient energy transfer processes in these systems.
van Oijen
A M
AM
Centre for the Study of Excited States of Molecules, Huygens Laboratory, Leiden University, 2300 RA Leiden, the Netherlands. antoine@molphys.leidenuniv.nl
Ketelaars
M
M
Köhler
J
J
Aartsma
T J
TJ
Schmidt
J
J
D004735:Energy Transfer; D007700:Kinetics; D008027:Light; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000528:radiation effects; D012241:Rhodopseudomonas / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins