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The absence of a spectroscopically resolved intermediate state P + B − in bacterial photosynthesis
Author(s) -
Breton J.,
Martin J.-L.,
Petrich J.,
Migus A.,
Antonetti A.
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)81080-8
Subject(s) - excited state , bacteriochlorophyll , chemistry , ultrafast laser spectroscopy , absorption band , photochemistry , rhodobacter sphaeroides , absorption (acoustics) , photosynthetic reaction centre , excitation , photosynthesis , laser , analytical chemistry (journal) , atomic physics , electron transfer , physics , optics , biochemistry , quantum mechanics , chromatography
Reaction centers from the photosynthetic bacterium Rhodopseudomonas sphaeroides have been excited either in the bacteriopheophytin band at 760 nm or in the accessory bacteriochlorophyll (B) band around 800 nm with laser pulses of 150 fs duration. Upon monitoring in the absorption band of the primary donor (P) at 860 nm, ultrafast energy transfer is observed which leads to the excited state of P in less than 100 fs. A transient bleaching recovering in 400 ± 100 fs is specifically detected upon excitation and observation in the 800 nm absorption band of B. However, upon direct excitation of P in the near infrared and using either normal or borohydride‐treated reaction centers, we have found no spectral or kinetic evidence indicating the presence of a transient intermediate state such as P + B − .