Purification and characterization of the B808-866 light-harvesting complex from green filamentous bacterium Chloroflexus aurantiacus

Yueyong Xin, Su Lin, Gabriel A. Montaño, Robert E. Blankenship

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The integral membrane light-harvesting complex B808-866 from the thermophilic green filamentous bacterium Chloroflexus aurantiacus has been isolated and characterized. Reversed-phase HPLC analysis demonstrated that the number of bacteriochlorophyll (BChl) in the B808-866 antenna complex is 36 ± 2 per reaction center. The main carotenoid type is γ-carotene, and the molar ratio of BChl to carotenoid is 3:2. The steady-state absorption and fluorescence spectroscopy of the B808-866 complex are reminiscent of the well-studied LH2 peripheral antenna of purple bacteria, whereas the protein sequence and the circular dichroism spectrum of B808-866 is more similar to the LH1 inner core antenna. The efficiency of excitation transfer from carotenoid to BChl is about 25%. The above results combined with electron microscopy and dynamic light scattering analysis suggest that the B808-866 antenna is more like the LH1, whereas surrounds the reaction center but probably consists of 24 building blocks with a ring diameter of about 20 nm. The above results suggested that there are probably two reaction centers inside the ring of B808-866. The unique properties of this light-harvesting complex may provide insights on the protein-pigment interactions in bacterial photosynthesis.

Original languageEnglish (US)
Pages (from-to)155-163
Number of pages9
JournalPhotosynthesis Research
Volume86
Issue number1-2
DOIs
StatePublished - Nov 2005

Fingerprint

Chloroflexus aurantiacus
Bacteriochlorophylls
light harvesting complex
Carotenoids
antennae
Purification
Bacteria
Antennas
Light
carotenoids
bacteria
Proteobacteria
fluorescence emission spectroscopy
Fluorescence Spectrometry
Photosynthesis
circular dichroism spectroscopy
Circular Dichroism
Electron Microscopy
Fluorescence spectroscopy
Proteins

Keywords

  • B808-866 light-harvesting complex
  • Characterization
  • Chloroflexus aurantiacus
  • Purification
  • Structure

ASJC Scopus subject areas

  • Plant Science

Cite this

Purification and characterization of the B808-866 light-harvesting complex from green filamentous bacterium Chloroflexus aurantiacus. / Xin, Yueyong; Lin, Su; Montaño, Gabriel A.; Blankenship, Robert E.

In: Photosynthesis Research, Vol. 86, No. 1-2, 11.2005, p. 155-163.

Research output: Contribution to journalArticle

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