Name of the laboratory:

Photobioenergetics

Phone:

(+994 12) 538 11 64

Fax:

(+994 12) 510 24 33 

E-mail:

photobioenergetics@imbb.science.az

Head of the laboratory:

Doctor of biological sciences Yashar Mirza Feyziyev

Staff:

junior researcher Konul Tofig Jumshudlu

junior researcher Parvin Etibar Safarova  

junior researcher Chilenay Mahammad Alakbarova

Main activity directions:

 Study of the primary processes of photosynthesis and structural-functional relationships;

 Study of the effect of various stress factors on the photosynthetic apparatus of plants;

 Investigation of energy production with the help of artificial models based on the initial reactions of photosynthesis

Main scientific achievements:

Electron transport was studied in the second photosystem and it was found that the efficiency of the primary photochemical reaction and electron transport in photosynthetic reaction centers (RC) is higher in the two-electron reduced state of plastoquinone than in the single-electron reduced state.

The recombination of oxidized chlorophyll P680+ and reduced pheophyte Ph– formed in the reaction center of PS2 during the initial photoreaction has been shown to be luminescence (recombination luminescence) from an excited chlorophyll molecule (P680*).

The energy barrier between the energy level of the ion-radical pair [P680 + Ph–] formed at the reaction center of PSII as a result of the initial photochemical reaction and the singlet excitation level of chlorophyll (P680*) was found to be 0.11-0.13 eV.

During a two-electron reduction of the plastoquinone acceptor in PSII, a new component of chlorophyll sensitive to the effects of external magnetic fields in the micro- and milliseconds range of chlorophyll delayed light radiation, with an activation energy of 0.5-0.6 eV was revealed and it was shown that this radiation was caused by the emission of a light quantum of during the return of the excited triplet (TP680) level of the chlorophyll molecule to the base level by successively passing through the triplet and singlet states of RC.

The role of bicarbonate ions was studied in PSII and it was found that the main site of the bicarbonate action was its electronic acceptor side. It was shown that bicarbonate is necessary for the regulation of electron transport between the electronic acceptors QA and QB of PSII, and it can also be involved in the regulation of catalytic reactions in PSII leading to the oxidation of water and the evolution of oxygen.

According to the experimental and theoretical data, oxidation of water by PSII is based on a metal-radical mechanism, which involves the participation of Mn-cluster, tyrosine Y_Z radical (YZ•), D1-His190 and other amino acids in the hydrogen bond with tyrosine. Transport of a proton and electron from a water molecule in contact with an Mn cluster to a tyrosine (YZ •) which transferred proton to lumen by D₁-His190.

In Ca2+ lacking PSII, the function of S-cycle in S2-S3 was restored at acidic pH values. Thus, Ca²⁺-+ -factor was shown to play an important role in regulating proton balance and proton flow as a component of the catalytic site where water is oxidized.

It has been shown that under physiological conditions, the pH of the lumen medium can control the electron transport at the catalytic site where water is oxidized by influencing the course of certain reactions (found in some transitions of the S-cycle). This, in turn, protects the secondary photosystem from damage by limiting the electron transport during the over-saturation of the reactions at the reaction center.

It was shown that together with tyrosine Y_D, Cyt b559 reduces electrons by giving electrons to the oxidized (S₂ and S₃) stages of the catalytic S-cycle of photosystem II. While the reduction of stage S3 is based on the competition between tyrosine YD and Cyt b559 determined by the redox state of the former, in the reduction of S2 stage, Cyt b559 is the dominant electron donor and participates in both direct and P680, YD, YZ and Car/D2-ChlZ-mediated electron transfer. In turn, this allows Cyt b559 to participate in the regulation of processes such as electron deficiency (or excess) in PSII under extreme conditions.

It has been found that it is possible to restore electron transport under the light in a second photosystem inhibited by the effects of thermal stress at high temperatures.