Photosynthesis Research

, Volume 140, Issue 1, pp 39–49 | Cite as

The influence of quaternary structure on the stability of Fenna–Matthews–Olson (FMO) antenna complexes

  • Rafael G. Saer
  • Rebecca L. Schultz
  • Robert E. BlankenshipEmail author
Original Article


The trimeric nature of the Fenna–Matthews–Olson (FMO) protein antenna complex from green sulfur phototrophic bacteria was investigated. Mutations were introduced into the protein at positions 142 and 198, which were chosen to destabilize the intra-trimer salt bridges between adjacent monomers. Strains bearing the mutations R142L, R198L, or their combination, exhibited altered optical absorption spectra of purified membranes and fluoresced more intensely than the wild type. In particular, the introduction of the R142L mutation resulted in slower culture growth rates, as well as an FMO complex that was not able to be isolated in appreciable quantities, while the R198L mutation yielded an FMO complex with increased sensitivity to sodium thiocyanate and Triton X-100 treatments. Native and denaturing PAGE experiments suggest that much of the FMO complexes in the mutant strains pool with the insoluble material upon membrane solubilization with n-dodecyl β-d-maltoside, a mild nonionic detergent. Taken together, our results suggest that the quaternary structure of the FMO complex, the homotrimer, is an important factor in the maintenance of the complex’s tertiary structure.


FMO Fenna–Matthews–Olson Bacteriochlorophyll Chlorobaculum tepidum Photosynthesis Light harvesting 







Optical density



This work was supported by the Photosynthetic Antenna Research Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC 0001035.

Author Contributions

REB and RGS designed the experiments. RGS and RS performed the experiments. RGS, RS, and REB analyzed the results. RGS and REB prepared the manuscript.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflicts of interest with the contents of this article.

Supplementary material

11120_2018_591_MOESM1_ESM.docx (416 kb)
Supplementary material 1 (DOCX 415 KB)


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Copyright information

© Springer Nature B.V. 2018

Authors and Affiliations

  • Rafael G. Saer
    • 1
    • 3
  • Rebecca L. Schultz
    • 2
    • 4
  • Robert E. Blankenship
    • 1
    • 2
    Email author
  1. 1.Department of BiologyWashington University in St. LouisSt. LouisUSA
  2. 2.Department of ChemistryWashington University in St. LouisSt. LouisUSA
  3. 3.Photosynthetic Antenna Research Center (PARC)Washington University in St. LouisSt. LouisUSA
  4. 4.Department of ChemistryUniversity of Wisconsin MadisonMadisonUSA

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