Femtosecond Dynamics of the Excited Primary Electron Donor in Reaction Centers of the Purple Bacterium Rhodobacter sphaeroides

• Published in: Biochemistry (Moscow) 2024-07, Vol.89 (7), p.1313-1324
• Main Authors: Khristin, Anton M., Fufina, Tatyana Yu, Khatypov, Ravil A.
• Format: Article
• Language: English
• Subjects: Absorption spectroscopy; Bacteria; Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Biochemistry; Biomedical and Life Sciences; Biomedicine; Bioorganic Chemistry; Charge transfer; Damping; Delay time; Electron states; Electron transfer; Electron Transport; Electrons; Energy; Excitation spectra; Internet resources; Life Sciences; Microbiology; Photosynthesis; Photosynthetic Reaction Center Complex Proteins - chemistry; Photosynthetic Reaction Center Complex Proteins - metabolism; Physics; Reaction centers; Rhodobacter sphaeroides; Rhodobacter sphaeroides - metabolism; Spectrum analysis; Vibration
• ISSN: 0006-2979; 1608-3040; 1608-3040
• DOI: 10.1134/S0006297924070125

Femtosecond transient absorption spectroscopy was used to study the dynamics of the excited primary electron donor in the reaction centers of the purple bacterium Rhodobacter sphaeroides . Using global analysis and the interval method, we found a correlation between the vibrational coherence damping of the excited primary electron donor and the lifetime of the charge-separated state P + B A − , indicating the reversibility of electron transfer to the primary electron acceptor, the B A molecule. In the reaction centers, the signs of superposition of two electronic states of P were found for a delay time of less than 200 fs. It is suggested that the admixture value of the charge transfer state P A + P B − with the excited primary electron donor P* is about 24%. The results obtained are discussed in terms of the two-step electron transfer mechanism.