Femtosecond resolution of ligand-heme interactions in the high-affinity quinol oxidase bd: a di-heme active site?

Vos, M.H.; Borisov, V.B.; Liebl, U.; Martin, J.L.; Konstantinov, A.A.

Статья опубликована в высокорейтинговом журнале

Информация о цитировании статьи получена из Web of Science, Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.

Авторы: Vos M.H., Borisov V.B., Liebl U., Martin J.L., Konstantinov A.A.
Журнал: Proceedings of the National Academy of Sciences of the United States of America
Том: 97
Номер: 4
Год издания: 2000
Издательство: National Academy of Sciences
Местоположение издательства: United States
Первая страница: 1554
Последняя страница: 1559
DOI: 10.1073/pnas.030528197
Аннотация: Interaction of the two high-spin hemes in the oxygen reduction site of the bd-type quinol oxidase from Escherichia coli has been studied by femtosecond multicolor transient absorption spectroscopy. The previously unidentified Soret band of ferrous heme b(595) was determined to be centered around 440 nm by selective excitation of the fully reduced unliganded or CO-bound cytochrome bd in the alpha-band of heme b(595). The redox state of the b-type hemes strongly affects both the line shape and the kinetics of the absorption changes induced by photodissociation of CO from heme d. In the reduced enzyme, CO photodissociation from heme d perturbs the spectrum of ferrous cytochrome b(595) within a few ps, pointing to a direct interaction between hemes b(595) and d. Whereas in the reduced enzyme no heme d-CO geminate recombination is observed, in the mixed-valence CO-liganded complex with heme b(595) initially oxidized, a significant part of photodissociated CO does not leave the protein and recombines with heme d within a few hundred ps. This caging effect may indicate that ferrous heme b(595) provides a transient binding site for carbon monoxide within one of the routes by which the dissociated ligand leaves the protein. Taken together, the data indicate physical proximity of the hemes d and b(595) and corroborate the possibility of a functional cooperation between the two hemes in the dioxygen-reducing center of cytochrome bd.
Добавил в систему: Борисов Виталий Борисович

	ИСТИНА	Войти в систему Регистрация
	ИПМех РАН
	Главная Поиск Статистика О проекте Помощь

ИСТИНА

ИПМех РАН

Femtosecond resolution of ligand-heme interactions in the high-affinity quinol oxidase bd: a di-heme active site?статья

Прикрепленные файлы