Circular dichroism measured on single chlorosomal light-harvesting complexes of green photosynthetic bacteria

Shu Furumaki, Yu Yabiku, Satoshi Habuchi, Yusuke Tsukatani, Donald A. Bryant, Martin Vácha

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


We report results on circular dichroism (CD) measured on single immobilized chlorosomes of a triple mutant of green sulfur bacterium Chlorobaculum tepidum. The CD signal is measured by monitoring chlorosomal bacteriochlorphyll c fluorescence excited by alternate left and right circularly polarized laser light with a fixed wavelength of 733 nm. The excitation wavelength is close to a maximum of the negative CD signal of a bulk solution of the same chlorosomes. The average CD dissymmetry parameter obtained from an ensemble of individual chlorosomes was gs = -0.025, with an intrinsic standard deviation (due to variations between individual chlorosomes) of 0.006. The dissymmetry value is about 2.5 times larger than that obtained at the same wavelength in the bulk solution. The difference can be satisfactorily explained by taking into account the orientation factor in the single-chlorosome experiments. The observed distribution of the dissymmetry parameter reflects the well-ordered nature of the mutant chlorosomes. © 2012 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)3545-3549
Number of pages5
JournalThe Journal of Physical Chemistry Letters
Issue number23
StatePublished - Nov 20 2012

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The work was supported by a Grant-in-Aid for Scientific Research No. 23651107 of the Japan Society for the Promotion of Science (M.V.).

ASJC Scopus subject areas

  • General Materials Science


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