Abstract
Chlorosomes are the principal light-harvesting bodies in green photosynthetic bacteria. These 100×30×12 nm ellipsoidal bodies contain ~104 bacteriochlorophyll (BChl) c chromophores, as well as a BChl a pigment-protein complex that forms an interfacial baseplate between the chlorosome and the cytoplasmic membrane. The BChl c pigments in chlorosomes are organized into large oligomers, whose electronic and vibrational spectroscopy is remarkably similar to that of BChl c aggregates that form spontaneously from BChl c monomers in solution. This unique self-aggregating property has attracted wide attention because of its potential applications in artificial photosynthesis. The BChl c and BChl a antennae of chlorosomes from the green bacterium Chloroflexus aurantiacus exhibit broad Qy (S1←S0) electronic absorption bands centered at ~740 and ~790 nm, respectively. Downhill BChl c → BChl a energy transfer occurs with ~10 ps kinetics in isolated chlorosomes [1,2]. In this work, we have focussed on the femtosecond internal energy transfer events within the BChl c antenna. It is currently believed [3] that this 740 nm antenna comprises several distinct BChl c spectral forms (c727, c744, c766 etc.) Equilibration among chlorophyll and bacteriochlorophyll spectral forms requires several hundred fs in most pigment-protein antenna complexes that have been studied to date [4].
© 1994 Optical Society of America
PDF ArticleMore Like This
S. Savikhin and W. S. Struve
TuE.21 International Conference on Ultrafast Phenomena (UP) 1996
S. Bradforth, R. Jimenez, V. Fidler, G. Fleming, S. Nagarajan, J. Norris, F. van Mourik, and R. van Grondelle
FB.3 International Conference on Ultrafast Phenomena (UP) 1994
J. Pšenčík, M. Vácha, F. Adamec, M. Ambrož, J. Dian, J. Boček, and J. Hála
TuB19 Spectral Hole-Burning and Luminescence Line Narrowing: Science and Applications (SHBL) 1992