Open AccessФемтосекундная абсорбционная спектроскопия восстановленной и окисленной форм цитохром c оксидазы: возбужденные состояния и релаксационные процессы в гемовых центрах a и a-=SUB=-3-=/SUB=-
Author(s) -
И.В. Шелаев,
Ф.Е. Гостев,
Т.В. Выгодина,
С. В. Лепешкевич,
Б. М. Джагаров
Publication year - 2019
Publication title -
žurnal tehničeskoj fiziki
Language(s) - English
Resource type - Journals
eISSN - 1726-748X
pISSN - 0044-4642
DOI - 10.21883/os.2019.10.48381.99-19
Subject(s) - photoexcitation , vibrational energy relaxation , heme a , relaxation (psychology) , picosecond , heme , chemistry , cytochrome c oxidase , ground state , excitation , ultrafast laser spectroscopy , raman spectroscopy , photochemistry , spectroscopy , atomic physics , excited state , molecule , physics , mitochondrion , optics , laser , psychology , social psychology , biochemistry , enzyme , organic chemistry , quantum mechanics
Excited electronic states and intraheme relaxation processes in the oxidized and reduced forms of mitochondrial cytochrome c oxidase extracted from a beef heart have been investigated by femtosecond absorption spectroscopy. The spectral and kinetic characteristics of short-lived intermediates have been measured from 80 fs to 20 ps after the photoexcitation. It is found that nonradiative electronic relaxation of the excitation energy in heme a , both in the oxidized (Fe(III) a ) and reduced (Fe(II) a ) forms, occurs successively as three processes, after the end of which heme a is in the ground state with a large store of vibrational energy. The subsequent vibrational relaxation (heme cooling) lasts for several picoseconds. It is found for reduced heme a _3 (Fe(II) a _3) that the electronic relaxation occurs as a result of two successive stages, which changes to vibrational relaxation in the ground state. The mechanism and dynamics of electronic excitation energy conversion in cytochrome c oxidase are analyzed.