Photosynthesis Research

, Volume 86, Issue 1, pp 113–121

Chlorosome Proteins Studied by MALDI-TOF-MS: Topology of CsmA in Chlorobium tepidum

  • Kirstin J. Milks
  • Marianne Danielsen
  • Søren Persson
  • Ole Nørregaard Jensen
  • Raymond P. Cox
  • Mette Miller
Regular Paper

DOI: 10.1007/s11120-005-3757-4

Cite this article as:
Milks, K.J., Danielsen, M., Persson, S. et al. Photosynth Res (2005) 86: 113. doi:10.1007/s11120-005-3757-4

Abstract

Chlorosomes, the light-harvesting apparatus of green bacteria, are a unique antenna system, in which pigments are organized in aggregates rather than associated with proteins. Isolated chlorosomes from the green sulphur bacterium Chlorobium tepidum contain 10 surface-exposed proteins. Treatment of chlorosomes from Chlorobium tepidum with protease caused changes in the spectral properties of bacteriochlorophyll c and digestion of chlorosome proteins. Using SDS-PAGE analysis, immunoblotting and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) we have investigated the topology of the 59-residue CsmA protein. Our results show that at the N-terminus, the only amino acid available for protease degradation is the methionine. At the C-terminus, amino acids can be removed by protease treatment to produce a residual protein containing at least the sequence between residues 2 and 38. These results indicate that the N-terminal portion of the CsmA protein, which is predicted to be mainly hydrophobic, is buried in the chlorosome envelope.

Keywords

chlorosomes CsmA green bacteria MALDI-TOF-MS 

Abbreviations

BChl

bacteriochlorophyll

DHB

2,5-dihydroxybenzoic acid

EDTA

ethylenediaminetetraacetic acid

MALDI-TOF-MS

matrix-assisted laser desorption ionization time of flight mass spectrometry

SDS

sodium dodecyl sulfate

TFA

trifluoroacetic acid

Copyright information

© Springer 2005

Authors and Affiliations

  • Kirstin J. Milks
    • 1
  • Marianne Danielsen
    • 1
  • Søren Persson
    • 1
  • Ole Nørregaard Jensen
    • 1
  • Raymond P. Cox
    • 1
  • Mette Miller
    • 1
  1. 1.Department of Biochemistry and Molecular BiologyUniversity of Southern DenmarkOdense MDenmark

Personalised recommendations