Main subjects of investigations are primary photosynthetic processes in light-gathering antennae and reaction centers (RCs).

Prof. V.A.Shuvalov's Group is studying the primary act of energy conversion of light excitation of primary electron donor (P) in bacterial RC. It comprises the electron transfer from P to bacteriochlorophyll monomer (Ba) within 1.6 ps at 10K, forming state P+Ba- . In native RC, an electron transfer from B- to bacteriopheophytin (Ha) takes place within 1 ps, in contrast to modified RC with Ha replaced by plant pheophytin (Ff) , in which the process is blocked at 10K, because the energy level of state P+Ba- is lower than that of state P+Ff -. In this case, only an electron transfer from Ba- to Qa takes place by means of superexchange using the Ff vacant orbital.

In the Laboratory of the Structure and Function of Light-harvesting Antennae (Dr. Z.G. Fetisova) the concept of strict functional optimization of light-harvesting antenna structure was put forward. Using simulations of excitation energy transfer (EET) from antenna to RC, some guiding principles for organization of an optimal antenna model were identified. Targeted searches for theoretically identified structural optimization criteria have subsequently allowed one to recognize them in natural antennae, in particular, in chlorosomal antennae of green bacteria. Namely:

The strong orientational ordering of the Qy-transition moments of bacteriochlorophyll (BChl) c in chlorosomes was discovered: the moments were shown to be mutually parallel and oriented along the chlorosome long axis.

It was shown theoretically that antenna pigment oligomerization is a biologically expedient strategy for light harvesting. The direct experimental proof of oligomeric organization of chlorosomal BChl c/e in intact cells of different green bacteria was demonstrated at the first time.

It was shown that none of the proposed for last 20 years models of a BChl aggregation in the chlorosome displays the in vivo exciton level structure of the aggregate. A new original model of chlorosomal pigment aggregation was proposed. A theory of EET developed explained antenna-size-dependent exciton dynamics in the chlorosome.

1. Shuvalov, V.A. (1990) Primary Light Energy Conversion at Photosynthesis. Moscow. Nauka. 212 p.

2. Franken, E.M., A.Ya. Shkuropatov, C.Francke, S. Neerken, P. Gast, V.A.Shuvalov, A.J. Hoff, T.J. Aartsma. Reaction centers of Rhodobacter sphaeroides R-26 with selective replacement of bacteriopheophytin by pheophytin a. Biochim.Biophys.Acta (1997), 1319, 242-250.

3. Fetisova, Z.G., Freiberg, A.M., Timpmann, K.E. Long-range molecular order as an efficient strategy for light harvesting in photosynthesis. Nature (1988) 334, 633-634.

4. Fetisova, Z.G., Shibaeva, L.V., Fok, M.V.Biological expedience of oligomerization of pigments in natural photosynthetic systems. J. Theor. Biol. (1989) 140, 167-184.

5. Fetisova, Z.G., Mauring, K. Experimental evidence of oligomeric organization of antenna bacteriochlorophyll c in green bacterium Chloroflexus aurantiacus by spectral hole burning. FEBS Letters (1993) 323, 159-162.

6. Fetisova, Z.G., Freiberg, A.M., Mauring, K., Novoderezhkin,V.I., Taisova, A.S., Timpmann, K.E. Excitation energy transfer in chlorosomes of green bacteria: theoretical and experimental studies. Biophys. J. (1996) 71, 995 -1010.