Sergei P. Balashov
Research Professor, Physiology & Biophysics
School of Medicine
School of Medicine
Ph.D., Moscow State University, 1979, Biophysics
University of California, Irvine
C355 Medical Sciences I
Mail Code: 4560
Irvine, CA 92697
C355 Medical Sciences I
Mail Code: 4560
Irvine, CA 92697
Research Interests
Light energy transformation in retinal membrane proteins: bacteriorhodopsin, archaerhodopsin, proteorhodopsin and xanthorhodopsin. Mechanisms of proton transport.
Research Abstract
I was fortunate to enter the bacteriorhodopsin (BR) field when little was known about its mechanism and the early stages of the light energy conversion. In order to detect and study the primary photoproducts I employed low temperature absorption spectroscopy and was able to trap early intermediates and found thermal branching and light-induced reactions in the photocycle. The latter finding (especially the phototransformation of the M intermediate) constitutes the basis for photoregulation of the photocycle and for potential applications of BR as a photochromic material in bioelectronics. The spectral and photochemical studies of the photocycle at low temperatures resulted in development of methods for trapping and identification of BR intermediates which is a key for investigation of bacteriorhodopsin and similar retinal proteins with X ray crystallography, FTIR spectroscopy and other methods.
Studies of bacteriorhodopsin mutants in 1990s at University of Illinois at Urbana-Champaign resulted in discovery of the mechanism of thermal isomerization through transient protonation of the chromophore’s counterion; and coupling of the counterion (and the primary proton acceptor) with the proton release complex through a long range interaction; identification of specific residues involved in proton transport. Some of the findings, such as the complex titration of ionizable residues and the coupling model describing it, have a general significance and is applicable to other membrane proteins.
Most recently the focus of my attention was xanthorhodopsin, a novel retinal protein proton pump with light harvesting carotenoid antenna which we discovered in extremely halophilic eubacteria Salinibacter ruber (Balashov et al. 2005. Science 309, 2061-2064). This protein is interesting not only as a unique example of efficient carotenoid to retinal energy transfer occurring from a short lived S2 state of carotenoid to S1 state of retinal, but as a microbial version of a proton pump with several features different from those of bacteriorhodopsin and archaerhodopsin.
Studies of bacteriorhodopsin mutants in 1990s at University of Illinois at Urbana-Champaign resulted in discovery of the mechanism of thermal isomerization through transient protonation of the chromophore’s counterion; and coupling of the counterion (and the primary proton acceptor) with the proton release complex through a long range interaction; identification of specific residues involved in proton transport. Some of the findings, such as the complex titration of ionizable residues and the coupling model describing it, have a general significance and is applicable to other membrane proteins.
Most recently the focus of my attention was xanthorhodopsin, a novel retinal protein proton pump with light harvesting carotenoid antenna which we discovered in extremely halophilic eubacteria Salinibacter ruber (Balashov et al. 2005. Science 309, 2061-2064). This protein is interesting not only as a unique example of efficient carotenoid to retinal energy transfer occurring from a short lived S2 state of carotenoid to S1 state of retinal, but as a microbial version of a proton pump with several features different from those of bacteriorhodopsin and archaerhodopsin.
Publications
BOOK AND BOOK CHAPTER
Balashov, S. P., and F. F. Litvin. 1985. Photochemical transformations of bacteriorhodopsin. A. A. Krasnovsky, ed., Moscow State University Press, Moscow, 164 pp.
Balashov, S. P., F. F. Litvin, and V. A. Sineshchekov. 1988. Photochemical processes of light energy transformation in bacteriorhodopsin. Physicochemical Biology Reviews 8, V. P. Skulachev, ed., Harwood Academic Publ., Switzerland. p. 1-61.
Balashov, S. P. and J. K. Lanyi. 2006. Bacteriorhodopsin. In: Microbial biotechnology. Biological self-assembly systems and biopolymer-based nanostructures (Rehn, B., Ed.), pp 339-366, Horizon bioscience, Norfolk.
SELECTED ARTICLES
Imasheva, E. S., S. P. Balashov, A. R. Choi, K.-H. Jung, J. K. Lanyi. 2009. Reconstitution of Gloeobacter violaceus rhodopsin with a light-harvesting carotenoid antenna. Biochemistry 48, 10948-10955.
Wu, J., D. Ma, Y. Wang, M. Ming, S. P. Balashov, and J. Ding. 2009. Efficient approach to determine the pKa of the proton release complex in the photocycle of retinal proteins. J. Phys. Chem. B. 113, 4482-4491.
Polívka, T., S. P. Balashov, P. Chábera, E. S. Imasheva, A. Yartsev, V. Sundström and J. K. Lanyi. 2009. Femtosecond Carotenoid to Retinal Energy Transfer in Xanthorhodopsin. Biophys. J. 96, 2268-2277.
Luecke, H., B. Schobert, J. Stagno, E. S. Imasheva, J. M. Wang, S. P. Balashov, and J. K. Lanyi. 2008. Crystallographic structure of xanthorhodopsin, the light-driven proton pump with a dual chromophore. Proc. Natl. Acad. Sci. U.S.A. 105, 16561-16565.
Balashov, S. P., E. S. Imasheva, J. M. Wang, and J. K. Lanyi. 2008. Excitation energy transfer and orientation of the chromophores in xanthorhodopsin. Biophys. J. 95, 2402-2414.
Lanyi, J. K., and S. P. Balashov. 2008. Xanthorhodopsin: a bacteriorhodopsin-like proton pump with a carotenoid antenna. Biochim. Biophys. Acta 1777, 684-688.
Imasheva, E. S., S. P. Balashov, J. M. Wang, E. Smolensky, M. Sheves, and J. K. Lanyi. 2008. Chromophore interaction in xanthorhodopsin: retinal-dependence of salinixanthin binding. Photochem. Photobiol. 84, 977-984.
Balashov, S. P., and J. K. Lanyi 2007. Xanthorhodopsin: proton pump with a carotenoid antenna. Cell. Mol. Life Sci. 64, 2323-2328.
Ming, M., M. Lu, S. P. Balashov, T. G. Ebrey, Q. G. Li, and J. D. Ding. 2006. pH dependence of light-driven proton pumping by an archaerhodopsin from Tibet: Comparison with bacteriorhodopsin. Biophys. J. 90, 3322-3332.
Imasheva, E. S., S. P. Balashov, J. M. Wang, and J. K. Lanyi. 2006. pH-dependent transitions in xanthorhodopsin. Photochem. Photobiol. 82, 1406-1413.
Boichenko, V. A., J. M. Wang, J. Antón, J. K. Lanyi, and S. P. Balashov. 2006. Functions of carotenoids in xanthorhodopsin and archaerhodopsin, from action spectra of photoinhibition of cell respiration. Biochim. Biophys. Acta 1757, 1649-1656.
Balashov, S. P., E. S. Imasheva, and J. K. Lanyi. 2006. Induced chirality of light-harvesting carotenoid salinixanthin and its interaction with the retinal of xanthorhodopsin. Biochemistry 45, 10998-11004.
Balashov, S. P., E. S. Imasheva, V. A. Boichenko, J. Anton, J. M. Wang, J. K. Lanyi. 2005. Xanthorhodopsin: a proton pump with a light-harvesting carotenoid antenna. Science 309, 5743, 2061-2064.
Maeda, A., F. L. Tomson, R. B. Gennis, S. P. Balashov, and T. G. Ebrey. 2003. Water molecule rearrangements around Leu93 and Trp182 in formation of the L intermediate in bacteriorhodopsin’s photocycle. Biochemistry 42, 2535-2541.
Balashov, S. P. and T. G. Ebrey. 2001. Trapping and spectroscopic identification of the photointermediates of bacteriorhodopsin at low temperatures. Photochem. Photobiol. 73, 453-462.
Balashov, S. P., M. Sumi, and N. Kamo. 2000. The M intermediate of phoborhodopsin is photoactive. Biophys. J. 78, 3150-3159.
Maeda, A., F. L. Tomson, R. B. Gennis, T. G. Ebrey, and S. P. Balashov. 2000. Relocation of internal bound water in bacteriorhodopsin during the photoreaction of M at low temperatures: An FTIR study. Biochemistry 39, 10154-10162.
Balashov, S. P. 2000. Protonation reactions and their coupling in bacteriorhodopsin. Biochim. Biophys. Acta 1460, 75-94.
Balashov, S. P., M. Lu, E. S. Imasheva, R. Govindjee, T. G. Ebrey, B. Othersen III, Y. Chen, R. K. Crouch, and D. R. Menick. 1999. The proton release group of bacteriorhodopsin controls the rate of the final step of its photocycle at low pH. Biochemistry 38, 2026-2039.
Maeda, A., F. L. Tomson, R. B. Gennis, T. G. Ebrey, and S. P. Balashov. 1999. Chromophore-Protein-Water interactions in the L intermediate of bacteriorhodopsin: FTIR study of photoreaction of L at 80 K. Biochemistry 38, 8800-8807.
Imasheva, E. S., S. P. Balashov, T. G. Ebrey, N. Chen, R. K. Crouch, and D. R. Menick. 1999. Two groups control light-induced Schiff base deprotonation and the proton affinity of aspartate-85 in the Arg82 -> His mutant of bacteriorhodopsin. Biophys. J. 77, 2750-2763.
Balashov, S. P., E. S. Imasheva, T. G. Ebrey, N. Chen, D. R. Menick, and R. K. Crouch. 1997. Glutamate-194 to cystein mutation inhibits fast light-induced proton release in bacteriorhodopsin. Biochemistry 36, 8671-8676.
Balashov, S. P., E. S. Imasheva, R. Govindjee, and T. G. Ebrey. 1996. Titration of aspartate-85 in bacteriorhodopsin: what it says about chromophore isomerization and proton release. Biophys. J. 70, 473-481.
Balashov, S. P., E. S. Imasheva, R. Govindjee, M. Sheves, and T. G. Ebrey. 1996. Light-induced purple-to-blue transition in bacteriorhodopsin: Evidence that Asp85 has a higher pKa in trans-bR than in 13-cis-bR. Biophys. J. 71, 1973-1984.
Balashov, S. P., R. Govindjee, E. S. Imasheva, S. Misra, T. G. Ebrey, Y. Feng, R. K. Crouch, and D. R. Menick. 1995. The two pKa’s of aspartate-85 and the control of thermal isomerization and proton release in the arginine-82 to lysine mutant of bacteriorhodopsin. Biochemistry 34, 8820-8834.
Balashov, S. P. 1995. Photoreactions of the photointermediates of bacteriorhodopsin. Isr. J. Chem. 35, 415-428.
Balashov, S. P., R. Govindjee, M. Kono, E. Imasheva, E. Lukashev, T. G. Ebrey, R. K. Crouch, D. R. Menick, and Y. Feng. 1993. Effect of the arginine-82 to alanine mutation in bacteriorhodopsin on dark adaptation, proton release and the photochemical cycle. Biochemistry 32, 10331-10343.
Balashov, S. P., R. Govindjee, and T. G. Ebrey. 1991. A red shift of purple membrane absorption band and deprotonation of tyrosine residues at high pH: origin of parallel photocycles of trans bacteriorhodopsin. Biophys. J. 60: 475-490.
Balashov, S. P., E. S. Imasheva, R. Govindjee, and T. G. Ebrey. 1991. Quantum yield ratio of the forward and back light reactions of bacteriorhodopsin at low temperature and photosteady-state concentration of bathoproduct K. Photochem. Photobiol. 54: 955-961
Balashov, S. P., N. V. Karneyeva, F. F. Litvin, and T. G. Ebrey. 1991. Bathoproducts and conformers of all-trans and 13-cis- bacteriorhodopsin at 90 K. Photochem. Photobiol. 54: 949-953.
Balashov, S. P., E. S. Imasheva, F. F. Litvin, and R. H. Lozier. 1990. The N intermediate of bacteriorhodopsin at low temperatures. Stabilization and photoconversion. FEBS Lett. 271: 93-96.
Govindjee, R., S. P. Balashov, and T. G. Ebrey. 1990. Quantum efficiency of the photochemical cycle of bacteriorhodopsin. Biophys. J. 58: 597-608.
Balashov, S. P., N. V. Karneyeva, E. S. Imasheva, and F. F. Litvin. 1986. Two forms of trans-bacteriorhodopsin and their photoreactions at 77 K. Biophysics 31: 981-984.
Balashov, S. P., and F. F. Litvin. 1981. Photochemical transformations of bacteriorhodopsin. Biophysics 26: 557-570.
Sineshchekov, V. A., S. P. Balashov, and F. F. Litvin. 1981. Fluorescence of photoactive bacteriorhodopsin. Biophysics 26: 964-972.
Litvin, F. F., and S. P. Balashov. 1977. New intermediates in the photoconversions of bacteriorhodopsin. Biophysics 22: 1111-1114.
Litvin, F. F., S. P. Balashov, and V. A. Sineshchekov. 1975. The investigation of the primary photochemical conversions of bacteriorhodopsin in purple membranes and cells of Halobacterium halobium by the low temperature spectrophotometry method. Bioorg. Chem. 1: 1767-1777.
Balashov, S. P., and F. F. Litvin. 1985. Photochemical transformations of bacteriorhodopsin. A. A. Krasnovsky, ed., Moscow State University Press, Moscow, 164 pp.
Balashov, S. P., F. F. Litvin, and V. A. Sineshchekov. 1988. Photochemical processes of light energy transformation in bacteriorhodopsin. Physicochemical Biology Reviews 8, V. P. Skulachev, ed., Harwood Academic Publ., Switzerland. p. 1-61.
Balashov, S. P. and J. K. Lanyi. 2006. Bacteriorhodopsin. In: Microbial biotechnology. Biological self-assembly systems and biopolymer-based nanostructures (Rehn, B., Ed.), pp 339-366, Horizon bioscience, Norfolk.
SELECTED ARTICLES
Imasheva, E. S., S. P. Balashov, A. R. Choi, K.-H. Jung, J. K. Lanyi. 2009. Reconstitution of Gloeobacter violaceus rhodopsin with a light-harvesting carotenoid antenna. Biochemistry 48, 10948-10955.
Wu, J., D. Ma, Y. Wang, M. Ming, S. P. Balashov, and J. Ding. 2009. Efficient approach to determine the pKa of the proton release complex in the photocycle of retinal proteins. J. Phys. Chem. B. 113, 4482-4491.
Polívka, T., S. P. Balashov, P. Chábera, E. S. Imasheva, A. Yartsev, V. Sundström and J. K. Lanyi. 2009. Femtosecond Carotenoid to Retinal Energy Transfer in Xanthorhodopsin. Biophys. J. 96, 2268-2277.
Luecke, H., B. Schobert, J. Stagno, E. S. Imasheva, J. M. Wang, S. P. Balashov, and J. K. Lanyi. 2008. Crystallographic structure of xanthorhodopsin, the light-driven proton pump with a dual chromophore. Proc. Natl. Acad. Sci. U.S.A. 105, 16561-16565.
Balashov, S. P., E. S. Imasheva, J. M. Wang, and J. K. Lanyi. 2008. Excitation energy transfer and orientation of the chromophores in xanthorhodopsin. Biophys. J. 95, 2402-2414.
Lanyi, J. K., and S. P. Balashov. 2008. Xanthorhodopsin: a bacteriorhodopsin-like proton pump with a carotenoid antenna. Biochim. Biophys. Acta 1777, 684-688.
Imasheva, E. S., S. P. Balashov, J. M. Wang, E. Smolensky, M. Sheves, and J. K. Lanyi. 2008. Chromophore interaction in xanthorhodopsin: retinal-dependence of salinixanthin binding. Photochem. Photobiol. 84, 977-984.
Balashov, S. P., and J. K. Lanyi 2007. Xanthorhodopsin: proton pump with a carotenoid antenna. Cell. Mol. Life Sci. 64, 2323-2328.
Ming, M., M. Lu, S. P. Balashov, T. G. Ebrey, Q. G. Li, and J. D. Ding. 2006. pH dependence of light-driven proton pumping by an archaerhodopsin from Tibet: Comparison with bacteriorhodopsin. Biophys. J. 90, 3322-3332.
Imasheva, E. S., S. P. Balashov, J. M. Wang, and J. K. Lanyi. 2006. pH-dependent transitions in xanthorhodopsin. Photochem. Photobiol. 82, 1406-1413.
Boichenko, V. A., J. M. Wang, J. Antón, J. K. Lanyi, and S. P. Balashov. 2006. Functions of carotenoids in xanthorhodopsin and archaerhodopsin, from action spectra of photoinhibition of cell respiration. Biochim. Biophys. Acta 1757, 1649-1656.
Balashov, S. P., E. S. Imasheva, and J. K. Lanyi. 2006. Induced chirality of light-harvesting carotenoid salinixanthin and its interaction with the retinal of xanthorhodopsin. Biochemistry 45, 10998-11004.
Balashov, S. P., E. S. Imasheva, V. A. Boichenko, J. Anton, J. M. Wang, J. K. Lanyi. 2005. Xanthorhodopsin: a proton pump with a light-harvesting carotenoid antenna. Science 309, 5743, 2061-2064.
Maeda, A., F. L. Tomson, R. B. Gennis, S. P. Balashov, and T. G. Ebrey. 2003. Water molecule rearrangements around Leu93 and Trp182 in formation of the L intermediate in bacteriorhodopsin’s photocycle. Biochemistry 42, 2535-2541.
Balashov, S. P. and T. G. Ebrey. 2001. Trapping and spectroscopic identification of the photointermediates of bacteriorhodopsin at low temperatures. Photochem. Photobiol. 73, 453-462.
Balashov, S. P., M. Sumi, and N. Kamo. 2000. The M intermediate of phoborhodopsin is photoactive. Biophys. J. 78, 3150-3159.
Maeda, A., F. L. Tomson, R. B. Gennis, T. G. Ebrey, and S. P. Balashov. 2000. Relocation of internal bound water in bacteriorhodopsin during the photoreaction of M at low temperatures: An FTIR study. Biochemistry 39, 10154-10162.
Balashov, S. P. 2000. Protonation reactions and their coupling in bacteriorhodopsin. Biochim. Biophys. Acta 1460, 75-94.
Balashov, S. P., M. Lu, E. S. Imasheva, R. Govindjee, T. G. Ebrey, B. Othersen III, Y. Chen, R. K. Crouch, and D. R. Menick. 1999. The proton release group of bacteriorhodopsin controls the rate of the final step of its photocycle at low pH. Biochemistry 38, 2026-2039.
Maeda, A., F. L. Tomson, R. B. Gennis, T. G. Ebrey, and S. P. Balashov. 1999. Chromophore-Protein-Water interactions in the L intermediate of bacteriorhodopsin: FTIR study of photoreaction of L at 80 K. Biochemistry 38, 8800-8807.
Imasheva, E. S., S. P. Balashov, T. G. Ebrey, N. Chen, R. K. Crouch, and D. R. Menick. 1999. Two groups control light-induced Schiff base deprotonation and the proton affinity of aspartate-85 in the Arg82 -> His mutant of bacteriorhodopsin. Biophys. J. 77, 2750-2763.
Balashov, S. P., E. S. Imasheva, T. G. Ebrey, N. Chen, D. R. Menick, and R. K. Crouch. 1997. Glutamate-194 to cystein mutation inhibits fast light-induced proton release in bacteriorhodopsin. Biochemistry 36, 8671-8676.
Balashov, S. P., E. S. Imasheva, R. Govindjee, and T. G. Ebrey. 1996. Titration of aspartate-85 in bacteriorhodopsin: what it says about chromophore isomerization and proton release. Biophys. J. 70, 473-481.
Balashov, S. P., E. S. Imasheva, R. Govindjee, M. Sheves, and T. G. Ebrey. 1996. Light-induced purple-to-blue transition in bacteriorhodopsin: Evidence that Asp85 has a higher pKa in trans-bR than in 13-cis-bR. Biophys. J. 71, 1973-1984.
Balashov, S. P., R. Govindjee, E. S. Imasheva, S. Misra, T. G. Ebrey, Y. Feng, R. K. Crouch, and D. R. Menick. 1995. The two pKa’s of aspartate-85 and the control of thermal isomerization and proton release in the arginine-82 to lysine mutant of bacteriorhodopsin. Biochemistry 34, 8820-8834.
Balashov, S. P. 1995. Photoreactions of the photointermediates of bacteriorhodopsin. Isr. J. Chem. 35, 415-428.
Balashov, S. P., R. Govindjee, M. Kono, E. Imasheva, E. Lukashev, T. G. Ebrey, R. K. Crouch, D. R. Menick, and Y. Feng. 1993. Effect of the arginine-82 to alanine mutation in bacteriorhodopsin on dark adaptation, proton release and the photochemical cycle. Biochemistry 32, 10331-10343.
Balashov, S. P., R. Govindjee, and T. G. Ebrey. 1991. A red shift of purple membrane absorption band and deprotonation of tyrosine residues at high pH: origin of parallel photocycles of trans bacteriorhodopsin. Biophys. J. 60: 475-490.
Balashov, S. P., E. S. Imasheva, R. Govindjee, and T. G. Ebrey. 1991. Quantum yield ratio of the forward and back light reactions of bacteriorhodopsin at low temperature and photosteady-state concentration of bathoproduct K. Photochem. Photobiol. 54: 955-961
Balashov, S. P., N. V. Karneyeva, F. F. Litvin, and T. G. Ebrey. 1991. Bathoproducts and conformers of all-trans and 13-cis- bacteriorhodopsin at 90 K. Photochem. Photobiol. 54: 949-953.
Balashov, S. P., E. S. Imasheva, F. F. Litvin, and R. H. Lozier. 1990. The N intermediate of bacteriorhodopsin at low temperatures. Stabilization and photoconversion. FEBS Lett. 271: 93-96.
Govindjee, R., S. P. Balashov, and T. G. Ebrey. 1990. Quantum efficiency of the photochemical cycle of bacteriorhodopsin. Biophys. J. 58: 597-608.
Balashov, S. P., N. V. Karneyeva, E. S. Imasheva, and F. F. Litvin. 1986. Two forms of trans-bacteriorhodopsin and their photoreactions at 77 K. Biophysics 31: 981-984.
Balashov, S. P., and F. F. Litvin. 1981. Photochemical transformations of bacteriorhodopsin. Biophysics 26: 557-570.
Sineshchekov, V. A., S. P. Balashov, and F. F. Litvin. 1981. Fluorescence of photoactive bacteriorhodopsin. Biophysics 26: 964-972.
Litvin, F. F., and S. P. Balashov. 1977. New intermediates in the photoconversions of bacteriorhodopsin. Biophysics 22: 1111-1114.
Litvin, F. F., S. P. Balashov, and V. A. Sineshchekov. 1975. The investigation of the primary photochemical conversions of bacteriorhodopsin in purple membranes and cells of Halobacterium halobium by the low temperature spectrophotometry method. Bioorg. Chem. 1: 1767-1777.
Grants
Study of Xanthorhodopsin, the Retinal Proton Pump of Salinibacter ruber with Light-Harvesting Carotenoid Antenna ARO W911NF-06-1-0020 (12/2005-2/2009)
Mechanisms of Energy Transfer and Photoconversions in Xanthorhodopsin. ARO W911NF-09-1-0243 (05/2009-05/2012)
Professional Societies
Biophysical Society
Link to this profile
https://faculty.uci.edu/profile/?facultyId=5520
https://faculty.uci.edu/profile/?facultyId=5520
Last updated
02/17/2010
02/17/2010