Academic Journal
Investigation of the Nature of the Excited-State of the Primary Electron Donor in the Purple Bacterial Reaction Centers: Femtosecond Absorption Spectroscopy of a Cereibacter sphaeroides Mutant with Blocked Electron Transfer.
| Τίτλος: | Investigation of the Nature of the Excited-State of the Primary Electron Donor in the Purple Bacterial Reaction Centers: Femtosecond Absorption Spectroscopy of a Cereibacter sphaeroides Mutant with Blocked Electron Transfer. |
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| Συγγραφείς: | Khristin, Anton M.1 (AUTHOR), Fufina, Tatiana Yu.1 (AUTHOR), Khatypov, Ravil A.1 (AUTHOR) rgreen1@rambler.ru |
| Πηγή: | Biochemistry (Moscow). Sep2026, Vol. 91 Issue 9, p1574-1586. 13p. |
| Θεματικοί όροι: | *Charge transfer, *Time-resolved spectroscopy, *Charge exchange, *Excited states, *Stimulated emission, *Photosynthetic reaction centers, *Excited state energies |
| Περίληψη: | Using femtosecond transient absorption spectroscopy, we investigated dynamics of absorption changes in the mutant reaction centers (RCs) of Cereibacter (C.) sphaeroides harboring the amino acid substitutions M160LH+L131LH+M197FH and M210YL, a combination known to block photoinduced charge separation. In these mutant RCs, formation of a long-lived excited state of the primary electron donor (P*) was observed. This state is characterized by stimulated emission that is red-shifted by 20 nm relative to that in the wild-type RCs. We hypothesize that the excited special-pair dimer adopts a charge-transfer state, (PAδ+PBδ−)*, which becomes long-lived under conditions where electron transfer is blocked in the mutant RC. On the energy scale, our data place the (PAδ+PBδ−)* state approximately 20 meV below the excitonic P* level. Within this framework, in the native RCs, the (PAδ+PBδ−)* charge-transfer state is short-lived and participates in ultrafast coherent electron-transfer reactions to the BA acceptor. [ABSTRACT FROM AUTHOR] |
| Βάση Δεδομένων: | Academic Search Index |
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