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

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.

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Abbreviations

FMO:

Fenna–Matthews–Olson

BChl:

Bacteriochlorophyll

OD:

Optical density

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

    Article  CAS  PubMed  PubMed Central  Google 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 194:214–222

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google Scholar 

  5. Blankenship RE (2014) Molecular mechanisms of photosynthesis, 2 edn. Wiley/Blackwell, Chichester

    Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  PubMed Central  Google 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

    Article  CAS  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  PubMed Central  Google 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

    Article  CAS  Google Scholar 

  23. Olson JM (1994) Reminiscence about Chloropseudomonas ethylicum and the FMO-protein. Photosynth Res 41:3–5. https://doi.org/10.1007/BF02184138

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  Google Scholar 

  34. Wahlund TM, Madigan MT (1995) Genetic transfer by conjugation in the thermophilic green sulfur bacterium Chlorobium tepidum. J Bacteriol 177:2583–2588

    Article  CAS  PubMed  PubMed Central  Google 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

    Article  PubMed  Google 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

    Article  CAS  PubMed  Google 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

    Article  CAS  PubMed  PubMed Central  Google 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

    Article  CAS  PubMed  Google Scholar 

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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.

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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.

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Correspondence to Robert E. Blankenship.

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Saer, R.G., Schultz, R.L. & Blankenship, R.E. The influence of quaternary structure on the stability of Fenna–Matthews–Olson (FMO) antenna complexes. Photosynth Res 140, 39–49 (2019). https://doi.org/10.1007/s11120-018-0591-z

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Keywords

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