Skip to main content
Log in

Why Is Electron Transport in the Reaction Centers of Purple Bacteria Unidirectional?

  • Published:
Biochemistry (Moscow) Aims and scope Submit manuscript

Abstract

Although the two electron-transfer branches in the reaction centers (RC) of purple bacteria are virtually symmetric, it is well known that only one of them is functionally active (the A-branch). The mechanisms of functional asymmetry of structurally symmetric branches of the electron transport system are analyzed in this work within the framework of the theory of bimolecular charge-transfer complexes (CTC). CTC theory is shown to provide an explanation of this phenomenon. According to the CTC theory, the dominance of one branch is required to implement the CTC state in special bacteriochlorophyll pairs of RC, in which more than 30% of the excited electron density in the CTC is shifted toward one of the bacteriochlorophyll molecules. This causes a significant increase in the efficiency of further electron transfer to the primary quinone acceptor as compared to a system with two absolutely symmetric electron transfer branches. Specific features of dielectric asymmetry near the RC special pair are discussed. It is emphasized that a strong CTC is able to provide effective trapping of electronic excitation energy from antenna chlorophyll, which is a main function of the RC. Hypothetical stages of CTC formation in other classes of photosynthesizing bacteria during evolution are discussed.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

REFERENCES

  1. Williams, J. C., Alden, R. G., Murchison, H. A., Peloquin, J. M., Woodbury, N. W., and Allen, J. P. (1992) Biochemistry, 31, 11029-11037.

    PubMed  Google Scholar 

  2. Heller, B. A., Holten, D., and Kirmaier, C. (1995) Science, 269, 940-945.

    Google Scholar 

  3. Rautter, J., Lendzian, F., Schultz, C., Fetsch, A., Kuhn, M., Lin, X., Williams, J. C., Allen, J. P., and Lubitz, W. (1995) Biochemistry, 34, 8130-8143.

    PubMed  Google Scholar 

  4. Taguchi, A. K. W., Eastman, J. E., Gallo, D. M., Jr., Xiao, W., and Woodbury, N. W. (1996) Biochemistry, 35, 3175-3186.

    PubMed  Google Scholar 

  5. Artz, K., Williams, J. C., Lendzian, J. P., Rautter, J., and Lubitz, W. (1997) Proc.Natl.Acad.Sci.USA, 94, 13582-13587.

    PubMed  Google Scholar 

  6. Kirmaier, C., and Holten, D. (1993) in The Photosynthetic Reaction Center (Deisenhofer, J., and Norris, J., eds.) Vol. 2, Academic Press, San Diego, pp. 4970.

    Google Scholar 

  7. Woodbury, N. W., and Allen, J. P. (1995) in Anoxygenic Photosynthetic Bacteria (Blankenship, R. E., Madigan, M. T., and Bauer, C. E., eds.) Kluwer Academic Publishers, The Netherlands, pp. 527-557.

    Google Scholar 

  8. Terenin, A. N. (1967) Photonics of Dye Molecules [in Russian], Nauka, Leningrad.

    Google Scholar 

  9. Grant, E. H., Sheppard, R. J., and South, G. H. (1968) Dielectric Behavior of Biological Molecules in Solution, Clarendon Press, Oxford, p. 137.

    Google Scholar 

  10. Davydov, A. N. (1976) The Solid State Theory [in Russian], Naukova Dumka, Kiev.

    Google Scholar 

  11. Van Grondelle, R., Dekker, J. P., Gilbro, T., and Sundstrem, V. (1994) Biochim.Biophys.Acta, 1187, 1-65.

    Google Scholar 

  12. Hoff, A. J. (1993) Molecular Physics, 78, 799-819.

    Google Scholar 

  13. Michel-Beyerle, M. E., Plato, M., Deisenhofer, J., Michel, H., Bixon, M., and Jortner, J. (1988) Biochim.Biophys.Acta, 932, 52-70.

    Google Scholar 

  14. Steffen, M. A., Lao, K., and Boxer, S. G. (1994) Science, 264, 810-816.

    Google Scholar 

  15. Moore, L. J., Zhou, H., and Boxer, S. G. (1999) Biochemistry, 38, 11949-11960.

    PubMed  Google Scholar 

  16. Parson, W. W., Chu, Z. T., and Warshel, A. (1990) Biochim.Biophys.Acta, 1017, 251-272.

    PubMed  Google Scholar 

  17. Kirmaier, C., Weems, D., and Holten, D. (1999) Biochemistry, 38, 11516-11530.

    PubMed  Google Scholar 

  18. Bylina, E. J., and Youvan, D. C. (1988) Proc.Natl.Acad.Sci.USA, 85, 7226-7230.

    Google Scholar 

  19. Shkuropatov, A. Ya., and Shuvalov, V. A. (1993) FEBS Lett., 322, 168-172.

    PubMed  Google Scholar 

  20. Fok, M. V., and Borisov, A. Y. (1981) Stud.Biophys., 32, 115-124.

    Google Scholar 

  21. Borisov, A. Y., and Fok, M. V. (1999) Biochem.Molec.Biol.Int., 47, 117-125.

    PubMed  Google Scholar 

  22. Kirmaier, C., Holten, D., Bylina, E. J., and Youvan, D. C. (1988) Proc.Natl.Acad.Sci.USA, 85, 7562-7566.

    PubMed  Google Scholar 

  23. McDowell, L. M., Gaul, D., Kirmaier, C., Holten, D., and Schenck, C. C. (1991) Biochemistry, 30, 8115-8122.

    Google Scholar 

  24. Ivancich, A., Artz, K., Williams, J. C., Allen, J. P., and Mattioli, T. (1998) Biochemistry, 37, 11812-11820.

    PubMed  Google Scholar 

  25. Ivancich, A., Mattioli, T., Artz, K., Wang, S., Allen, J. P., and Williams, J. C. (1997) Biochemisrty, 36, 3027-3036.

    Google Scholar 

  26. Sakurai, H., Kusumoto, N., and Injue, K. (1996) Photochem.Photobiol., 64, 5-13.

    Google Scholar 

  27. Tserniker, Y. L., and Chetverikov, A. G. (1988) Photosynthetica, 22, 483-490.

    Google Scholar 

  28. Bolton, J. R. (ed.) (1977) Solar Power and Fuels, Academic Press, N. Y.

    Google Scholar 

  29. Skulachev, V. P. (1989) Energetics of Biological Membranes [in Russian], Nauka, Moscow.

    Google Scholar 

  30. Schubert, W. D., Klukas, O., Kraus, N., Saenger, W., Fromme, P., and Witt, H. T. (1997) J.Mol.Biol., 272, 741-769.

    PubMed  Google Scholar 

  31. Foerster, T. (1948) Ann.Physik., 2, 55-75.

    Google Scholar 

  32. Ermler, U., Fritzsch, G., Buchanan, S. K., and Michel, H. (1994) Structure, 2, 925-936.

    Article  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Borisov, A.Y. Why Is Electron Transport in the Reaction Centers of Purple Bacteria Unidirectional?. Biochemistry (Moscow) 65, 1429–1434 (2000). https://doi.org/10.1023/A:1002865109271

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1023/A:1002865109271

Navigation