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

  • Rafael G. Saer
  • Rebecca L. Schultz
  • Robert E. Blankenship
Original Article
  • 14 Downloads

Abstract

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.

Keywords

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

Abbreviations

FMO

Fenna–Matthews–Olson

BChl

Bacteriochlorophyll

OD

Optical density

Notes

Acknowledgements

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)

References

  1. Adolphs J, Renger T (2006) How proteins trigger excitation energy transfer in the FMO complex of green sulfur bacteria. Biophys J 91:2778–2797.  https://doi.org/10.1529/biophysj.105.079483 CrossRefPubMedPubMedCentralGoogle Scholar
  2. Allen KD, Staehelin LA (1991) Resolution of 16 to 20 chlorophyll-protein complexes using a low ionic strength native green gel system. Anal Biochem 194:214–222CrossRefGoogle Scholar
  3. Ben-Shem A, Frolow F, Nelson N (2004) Evolution of photosystem I—from symmetry through pseudosymmetry to asymmetry. FEBS Lett 564:274–280.  https://doi.org/10.1016/S0014-5793(04)00360-6 CrossRefPubMedGoogle Scholar
  4. Bina D, Blankenship RE (2013) Chemical oxidation of the FMO antenna protein from Chlorobaculum tepidum. Photosynth Res 116:11–19.  https://doi.org/10.1007/s11120-013-9878-2 CrossRefPubMedGoogle Scholar
  5. Blankenship RE (2014) Molecular mechanisms of photosynthesis, 2 edn. Wiley/Blackwell, ChichesterGoogle Scholar
  6. Brixner T, Stenger J, Vaswani HM et al (2005) Two-dimensional spectroscopy of electronic couplings in photosynthesis. Nature 434:625–628.  https://doi.org/10.1038/nature03429 CrossRefPubMedGoogle Scholar
  7. Bryant DA, Costas AMG, Maresca JA et al (2007) Candidatus Chloracidobacterium thermophilum: an aerobic phototrophic Acidobacterium. Science 317:523–526.  https://doi.org/10.1126/science.1143236 CrossRefGoogle Scholar
  8. Dostál J, Pšenčík J, Zigmantas D (2016) In situ mapping of the energy flow through the entire photosynthetic apparatus. Nat Chem 8:705–710.  https://doi.org/10.1038/nchem.2525 CrossRefPubMedGoogle Scholar
  9. Fenna RE, Matthews BW (1975) Chlorophyll arrangement in a bacteriochlorophyll protein from Chlorobium limicola. Nature 258:573–577.  https://doi.org/10.1038/258573a0 CrossRefGoogle Scholar
  10. Fenna RE, Matthews BW, Olson JM, Shaw EK (1974) Structure of a bacteriochlorophyll-protein from the green photosynthetic bacterium Chlorobium limicola: crystallographic evidence for a trimer. J Mol Biol 84:231–240.  https://doi.org/10.1016/0022-2836(74)90581-6 CrossRefPubMedGoogle Scholar
  11. Frigaard N-U, Bryant DA (2001) Chromosomal Gene inactivation in the green sulfur bacterium Chlorobium tepidum by natural transformation. Appl Environ Microbiol 67:2538–2544.  https://doi.org/10.1128/AEM.67.6.2538-2544.2001 CrossRefPubMedPubMedCentralGoogle Scholar
  12. Gallivan JP, Dougherty DA (1999) Cation-pi interactions in structural biology. Proc Natl Acad Sci 96:9459–9464.  https://doi.org/10.1073/pnas.96.17.9459 CrossRefPubMedGoogle Scholar
  13. Ghosh AK, Olson JM (1968) Effects of denaturants on the absorption spectrum of the bacteriochlorophyll-protein from the photosynthetic bacterium Chloropseudomonas ethylicum. Biochim Biophys Acta BBA 162:135–148.  https://doi.org/10.1016/0005-2728(68)90221-1 CrossRefPubMedGoogle Scholar
  14. Gottstein J, Scheer H (1983) Long-wavelength-absorbing forms of bacteriochlorophyll a in solutions of Triton X-100. Proc Natl Acad Sci 80:2231–2234.  https://doi.org/10.1073/pnas.80.8.2231 CrossRefPubMedGoogle Scholar
  15. Gottstein J, Scherz A, Scheer H (1993) Bacteriochlorophyll aggregates in positively charged micelles. Biochim Biophys Acta BBA 1183:413–416.  https://doi.org/10.1016/0005-2728(93)90247-D CrossRefPubMedGoogle Scholar
  16. Herascu N, Kell A, Acharya K et al (2014) Modeling of various optical spectra in the presence of slow excitation energy transfer in dimers and trimers with weak interpigment coupling: FMO as an example. J Phys Chem B 118:2032–2040.  https://doi.org/10.1021/jp410586f CrossRefPubMedGoogle Scholar
  17. Johnson SG, Small GJ (1991) Excited-state structure and energy-transfer dynamics of the bacteriochlorophyll a antenna complex from Prosthecochloris aestuarii. J Phys Chem 95:471–479.  https://doi.org/10.1021/j100154a083 CrossRefGoogle Scholar
  18. Kell A, Acharya K, Zazubovich V, Jankowiak R (2014) On the controversial nature of the 825 nm exciton band in the FMO protein complex. J Phys Chem Lett 5:1450–1456.  https://doi.org/10.1021/jz5001165 CrossRefPubMedGoogle Scholar
  19. Kell A, Blankenship RE, Jankowiak R (2016) Effect of spectral density shapes on the excitonic structure and dynamics of the Fenna–Matthews–Olson trimer from Chlorobaculum tepidum. J Phys Chem A 120:6146–6154.  https://doi.org/10.1021/acs.jpca.6b03107 CrossRefPubMedGoogle Scholar
  20. Li Y-F, Zhou W, Blankenship RE, Allen JP (1997) Crystal structure of the bacteriochlorophyll a protein from Chlorobium tepidum 1. J Mol Biol 271:456–471.  https://doi.org/10.1006/jmbi.1997.1189 CrossRefPubMedGoogle Scholar
  21. Li C, Wen A, Shen B et al (2011) FastCloning: a highly simplified, purification-free, sequence- and ligation-independent PCR cloning method. BMC Biotechnol 11:92.  https://doi.org/10.1186/1472-6750-11-92 CrossRefPubMedPubMedCentralGoogle Scholar
  22. Namsaraev ZB (2009) Application of extinction coefficients for quantification of chlorophylls and bacteriochlorophylls. Microbiology 78:794–797.  https://doi.org/10.1134/S0026261709060174 CrossRefGoogle Scholar
  23. Olson JM (1994) Reminiscence about Chloropseudomonas ethylicum and the FMO-protein. Photosynth Res 41:3–5.  https://doi.org/10.1007/BF02184138 CrossRefPubMedGoogle Scholar
  24. Orf GS, Blankenship RE (2013) Chlorosome antenna complexes from green photosynthetic bacteria. Photosynth Res 116:315–331.  https://doi.org/10.1007/s11120-013-9869-3 CrossRefPubMedGoogle Scholar
  25. Pearlstein RM (1992) Theory of the optical spectra of the bacteriochlorophyll a antenna protein trimer from Prosthecochloris aestuarii. Photosynth Res 31:213–226.  https://doi.org/10.1007/BF00035538 CrossRefPubMedGoogle Scholar
  26. Rätsep M, Freiberg A (2007) Unusual temperature quenching of bacteriochlorophyll a fluorescence in FMO antenna protein trimers. Chem Phys Lett 434:306–311.  https://doi.org/10.1016/j.cplett.2006.12.013 CrossRefGoogle Scholar
  27. Saer RG, Blankenship RE (2017) Light harvesting in phototrophic bacteria: structure and function. Biochem J 474:2107–2131.  https://doi.org/10.1042/BCJ20160753 CrossRefPubMedGoogle Scholar
  28. Saer R, Orf GS, Lu X et al (2016) Perturbation of bacteriochlorophyll molecules in Fenna–Matthews–Olson protein complexes through mutagenesis of cysteine residues. Biochim Biophys Acta BBA 1857:1455–1463.  https://doi.org/10.1016/j.bbabio.2016.04.007 CrossRefPubMedGoogle Scholar
  29. Saer RG, Stadnytskyi V, Magdaong NC et al (2017) Probing the excitonic landscape of the Chlorobaculum tepidum Fenna–Matthews–Olson (FMO) complex: a mutagenesis approach. Biochim Biophys Acta 1858:288–296.  https://doi.org/10.1016/j.bbabio.2017.01.011 CrossRefGoogle Scholar
  30. Schmidt am Busch M, Müh F, El-Amine Madjet M, Renger T (2011) The eighth bacteriochlorophyll completes the excitation energy funnel in the FMO protein. J Phys Chem Lett 2:93–98.  https://doi.org/10.1021/jz101541b CrossRefPubMedGoogle Scholar
  31. Thyrhaug E, Žídek K, Dostál J et al (2016) Exciton structure and energy transfer in the Fenna–Matthews–Olson complex. J Phys Chem Lett 7:1653–1660.  https://doi.org/10.1021/acs.jpclett.6b00534 CrossRefPubMedGoogle Scholar
  32. Tronrud DE, Wen J, Gay L, Blankenship RE (2009) The structural basis for the difference in absorbance spectra for the FMO antenna protein from various green sulfur bacteria. Photosynth Res 100:79–87.  https://doi.org/10.1007/s11120-009-9430-6 CrossRefPubMedGoogle Scholar
  33. Tsukatani Y, Wen J, Blankenship RE, Bryant DA (2010) Characterization of the FMO protein from the aerobic chlorophototroph, Candidatus Chloracidobacterium thermophilum. Photosynth Res 104:201–209.  https://doi.org/10.1007/s11120-009-9517-0 CrossRefPubMedGoogle Scholar
  34. Wahlund TM, Madigan MT (1995) Genetic transfer by conjugation in the thermophilic green sulfur bacterium Chlorobium tepidum. J Bacteriol 177:2583–2588CrossRefGoogle Scholar
  35. Wen J, Zhang H, Gross ML, Blankenship RE (2009) Membrane orientation of the FMO antenna protein from Chlorobaculum tepidum as determined by mass spectrometry-based footprinting. Proc Natl Acad Sci 106:6134–6139.  https://doi.org/10.1073/pnas.0901691106 CrossRefPubMedGoogle Scholar
  36. Wen J, Tsukatani Y, Cui W et al (2011a) Structural model and spectroscopic characteristics of the FMO antenna protein from the aerobic chlorophototroph, Candidatus Chloracidobacterium thermophilum. Biochim Biophys Acta BBA 1807:157–164.  https://doi.org/10.1016/j.bbabio.2010.09.008 CrossRefPubMedGoogle Scholar
  37. Wen J, Zhang H, Gross ML, Blankenship RE (2011b) Native electrospray mass spectrometry reveals the nature and stoichiometry of pigments in the FMO photosynthetic antenna protein. Biochemistry 50:3502–3511.  https://doi.org/10.1021/bi200239k CrossRefPubMedPubMedCentralGoogle Scholar
  38. Zhou W, LoBrutto R, Lin S, Blankenship RE (1994) Redox effects on the bacteriochlorophyll α-containing Fenna–Matthews–Olson protein from Chlorobium tepidum. Photosynth Res 41:89–96.  https://doi.org/10.1007/BF02184148 CrossRefPubMedGoogle Scholar

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
  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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