The light-harvesting complex II of the purple bacteria has two strong near infrared electronic absorption bands, around 800 (B800) and 850 (B850) nm, arising from the Qy transitions of bacteriochlorophyll a. It was previously reported that under some specific acid/chaotropic conditions the B850 bacteriochlorophylls of the light-harvesting complex II of Ectothiorhodospira sp. are strongly reorga...

Plants dissipate excess excitation energy as heat by non-photochemical quenching (NPQ). NPQ has been thought to resemble in vitro aggregation quenching of the major antenna complex, light harvesting complex of photosystem II (LHC-II). Both processes are widely believed to involve a conformational change that creates a quenching centre of two neighbouring pigments within the complex. Using recom...

Light-harvesting complex II (LHCII) contains three highly homologous chlorophyll-a/b-binding proteins (Lhcb1, Lhcb2 and Lhcb3), which can be assembled into both homo- and heterotrimers. Lhcb1 and Lhcb2 are reversibly phosphorylated by the action of STN7 kinase and PPH1/TAP38 phosphatase in the so-called state-transition process. We have developed antibodies that are specific for the phosphoryla...

Recently developed approaches to simulate environment-induced fluctuation effects in two-dimensional (2D) spectroscopy of excitons are compared for the Fenna-Matthews-Olson light-harvesting complex. Fast fluctuations induce population redistribution between exciton energy-levels and raise homogeneous line widths of various peaks in 2D spectra. These effects are easily accounted for in sum-over-...

Time-resolved ultrafast optical probes of chiral dynamics provide a new window allowing us to explore how interactions with such structured environments drive electronic dynamics. Incorporating optical activity into time-resolved spectroscopies has proven challenging because of the small signal and large achiral background. Here we demonstrate that two-dimensional electronic spectroscopy can be...

Two-dimensional Fourier transform electronic spectroscopy is employed to investigate quantum beating in the major light-harvesting complex II. Long-lived excitonic coherence is observed for the first time in a higher plant system between two different types of chlorophyll molecules.

Electron diffraction patterns of two-dimensional crystals of light-harvesting chlorophyll a/b-protein complex (LHC-II) from photosynthetic membranes of pea chloroplasts, tilted at different angles up to 60 degrees , were collected to 3.2 A resolution at -125 degrees C. The reflection intensities were merged into a three-dimensional data set. The Friedel R-factor and the merging R-factor were 21...

Trying to detect the genes coding for light harvesting II polypeptides of the purple bacteria Ectothiorhodospira sp. a gene corresponding to a light harvesting I polypeptide was cloned. This paper discusses the probable reasons of this result. The sequence of this polypeptide underlines the strong similarity with light harvesting complexes from bacteria such as Rhodospirillum molischianum and C...

A generic and intuitive model for coherent energy transport in multiple minima systems coupled to a quantum mechanical bath is shown. Using a simple spin-boson system, we illustrate how a generic donor-acceptor system can be brought into resonance using a narrow band of vibrational modes, such that the transfer efficiency of an electron-hole pair (exciton) is made arbitrarily high. Coherent tra...