Photosynthesis Research

, Volume 31, Issue 3, pp 213–226 | Cite as

Theory of the optical spectra of the bacteriochlorophyll a antenna protein trimer from Prosthecochloris aestuarii

  • Robert M. Pearlstein
Regular Paper


A reasonable theoretical fit to the experimental low-temperature absorption and CD spectra of the BChl a-protein from Prosthecochloris aestuarii has been obtained for the unaggregated protein trimer based on standard assumptions regarding QY transition moment directions. The fits depend to some extent upon varying the site wavelengths of the individual BChls not just in one subunit but in the entire trimer, a procedure not tried before. Features in both spectra, but especially in CD, at wavelengths longer than ≈810 nm are very strongly influenced by the intersubunit interactions of BChls 7 (in the Fenna-Matthews numbering). Unlike earlier theoretical models, which also gave reasonable fits but were based on unorthodox or incorrect assumptions, this exciton model gives every indication of being refineable by improved choices of site wavelengths and exciton-transition lineshapes. Calculated exciton-transition wavelengths and line widths are compared with values deduced from recent laser hole-burning experiments (Johnson and Small 1991). As in the case of the absorption and CD spectra, agreement is best for the long-wavelength half of the QY region.

Key words

circular dichroism exciton states laser hole-burning photosynthetic bacteria protein structure 



circular dichroism




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  1. Fenna RE and Matthews BW (1975) Chlorophyll arrangement in a bacteriochlorophyll protein from Chlorobium limicola. Nature 258: 573–577Google Scholar
  2. Fenna RE, tenEyck LF and Matthews BW (1977) Atomic coordinates for the chlorophyll core of a bacteriochlorophyll a-protein from green photosynthetic bacteria. Biochem Biophys Res Commun 75: 751–756Google Scholar
  3. Gudowska-Nowak E, Newton MD and Fajer J (1990) Conformational and environmental effects on bacteriochlorophyll optical spectra: Correlations of calculated spectra with structural results. J Phys Chem 94: 5795–5801Google Scholar
  4. Hanson LK (1988) Theoretical calculations of photosynthetic pigments. Photochem Photobiol 47: 903–921Google Scholar
  5. Johnson SG and Small GJ (1991) Excited-state structure and energy-transfer dynamics of the bacteriochlorophyll a antenna complex from Prosthecochloris aestuarii. J Phys Chem 95: 471–479Google Scholar
  6. Matthews BW, Fenna RE and Remington SJ (1977) An evaluation of electron micrographs of bacteriochlorophyll a-protein crystals in terms of the structure determined by x-ray crystallography. J Ultrastruc Res 58: 316–330Google Scholar
  7. Matthews BW, Fenna RE, Bolognesi MC, Schmid MF and Olson JM (1979) Structure of a bacteriochlorophyll a-protein from the green photosynthetic bacterium Prosthecochloris aestuarii. J Mol Biol 131: 259–285Google Scholar
  8. Meister A (1986) Calculation of exciton interaction between subunits of bacteriochlorophyll-protein from Prosthecochloris aestuarii. Studia Biophys 113: 171–176Google Scholar
  9. Olson JM (1966) Chlorophyll-protein complexes part II. Complexes derived from green photosynthetic bacteria. In: Vernon LF and Seely GR (eds) The Chlorophylls, pp 413–425. Academic Press, New YorkGoogle Scholar
  10. Olson JM, Ke B and Thompson KH (1976) Exciton interactions among chlorophyll molecules in bacteriochlorophyll a proteins and bacteriochlorophyll a reaction center complexes from green bacteria. Biochim Biophys Acta 430: 524–537Google Scholar
  11. Pearlstein RM (1982) Chlorophyll singlet excitons. In: Govindjee (ed) Photosynthesis: Energy Conversion by Plants and Bacteria, Vol 1, pp 293–330. Academic Press, New YorkGoogle Scholar
  12. Pearlstein RM (1987) Structure and exciton effects in photosynthesis. In: Amesz J (ed) Photosynthesis, pp 299–317. Elsevier Science Publishers BV, AmsterdamGoogle Scholar
  13. Pearlstein RM (1988) Interpretation of optical spectra of bacteriochlorophyll antenna complexes. In: Scheer H and Schneider S (eds) Photosynthetic Light Harvesting Systems, pp 555–566. Walter de Gruyter and Co, BerlinGoogle Scholar
  14. Pearlstein RM (1991) Theoretical interpretation of antenna spectra. In: Scheer H (ed) Chlorophylls, pp 1047–1078. CRC Press, Boca RatonGoogle Scholar
  15. Pearlstein RM and Hemenger RP (1978) Bacteriochlorophyll electronic transition moment directions in bacteriochlorophyll a-protein. Proc Natl Acad Sci USA 75: 4920–4924Google Scholar
  16. Pearlstein RM and Zuber H (1985) Exciton states and energy transfer in bacterial membranes: The role of pigment-protein cyclic unit structures. In: Michel-Beyerle ME (ed) Antennas and Reaction Centers of Photosynthetic Bacteria, pp 53–61. Springer-Verlag, BerlinGoogle Scholar
  17. Philipson KD and Sauer K (1972) Exciton interaction in a bacteriochlorophyll-protein from Chloropseudomonas ethylica. Absorption and circular dichroism at 77 K. (1972) Biochem 11: 1880–1885Google Scholar
  18. Swarthoff T, deGrooth BG, Meiburg RF, Rijgersberg CP and Amesz J (1980) Orientation of pigments and pigment-protein complexes in the green photosynthetic bacterium Prosthecochloris aestuarii. Biochim Biophys Acta 593: 51–59Google Scholar
  19. Tronrud DE, Schmid MF and Matthews BW (1986) Structure and x-ray amino acid sequence of a bacteriochlorophyll a protein from Prosthecochloris aestuarii refined at 1.9 Å resolution. J Mol Biol 188: 443–454Google Scholar
  20. Weiss C (1972) The pi electron structure and absorption spectra of chlorophylls in solution. J Mol Spectrosc 44: 37–80Google Scholar
  21. Whitten WB, Nairn JA and Pearlstein RM (1978a) Derivative absorption spectroscopy from 5–300 K of bacteriochlorophyll a-protein from Prosthecochloris aestuarii. Biochim Biophys Acta 503: 251–262Google Scholar
  22. Whitten WB, Pearlstein RM, Phares EF and Geacintov NE (1978b) Linear dichroism of electric field oriented bacteriochlorophyll a-protein from green photosynthetic bacteria. Biochim Biophys Acta 503: 491–498Google Scholar
  23. Whitten WB, Olson JM and Pearlstein RM (1980) Sevenfold exciton splitting of the 810-nm band in bacteriochlorophyll a-proteins from green photosynthetic bacteria. Biochim Biophys Acta 591: 203–207Google Scholar

Copyright information

© Kluwer Academic Publishers 1992

Authors and Affiliations

  • Robert M. Pearlstein
    • 1
  1. 1.Physics DepartmentIndiana-Purdue UniversityIndianapolisUSA

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