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Femtosecond kinetics of electron transfer in the bacteriochlorophyll M ‐modified reaction centers from Rhodobacter sphaeroides (R‐26)
Author(s) -
Yakovlev A.G.,
Shkuropatov A.Ya.,
Shuvalov V.A.
Publication year - 1996
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(96)00113-5
Subject(s) - rhodobacter sphaeroides , bacteriochlorophyll , electron transfer , chemistry , excited state , wave packet , photosynthetic reaction centre , electron , kinetics , femtosecond , photochemistry , excitation , atomic physics , physics , laser , photosynthesis , optics , biochemistry , quantum mechanics
Formation of the vibronic wavepacket by 90‐fs excitation of the primary electron donor P in bacteriochlorophyll M ‐modified reaction centers is shown to induce nuclear motions accompanied by (1) oscillation of the stimulated emission from excited primary electron donor P ∗ and (2) wavepacket motions leading to electron transfer at 293 K from P ∗ to bacteriochlorophyll (B L ) and then to bacteriopheophytin (H L ). The latter motions have low frequency (about 15 cm −1 ) and are related to protein‐nuclear motions which are along the reaction coordinate. When the wavepacket approaches the intersection of the reactant (P ∗ B L ) and product (P + B L −) potential energy surfaces (∼1.5 ps delay), about 60% of P ∗ is converted to the P + B L − state. The P + H L − state formation is delayed by ∼2 ps with respect to that of P + B L −. It is suggested that the wavepacket is transferred to and moves also slowly on the P + B L − potential energy surface and approaches the intersection of the surfaces of P + B L − and P + H L − within ∼2 ps (∼8 cm −1 ), indicating the electron transfer to H L .