Observing heme doming in myoglobin with femtosecond X-ray absorption spectroscopya)

We report time-resolved X-ray absorption measurements after photolysis of carbonmonoxy myoglobin performed at the LCLS X-ray free electron laser with nearly 100 fs (FWHM) time resolution. Data at the Fe K-edge reveal that the photoinduced structural changes at the heme occur in two steps, with a fas...

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Detalles Bibliográficos
Autores principales: Levantino, M., Lemke, H. T., Schirò, G., Glownia, M., Cupane, A., Cammarata, M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Crystallographic Association 2015
Materias:
SPECIAL TOPIC: BIOLOGY WITH X-RAY LASERS 2
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4711634/
https://www.ncbi.nlm.nih.gov/pubmed/26798812
http://dx.doi.org/10.1063/1.4921907
Descripción
Sumario:We report time-resolved X-ray absorption measurements after photolysis of carbonmonoxy myoglobin performed at the LCLS X-ray free electron laser with nearly 100 fs (FWHM) time resolution. Data at the Fe K-edge reveal that the photoinduced structural changes at the heme occur in two steps, with a faster (∼70 fs) relaxation preceding a slower (∼400 fs) one. We tentatively attribute the first relaxation to a structural rearrangement induced by photolysis involving essentially only the heme chromophore and the second relaxation to a residual Fe motion out of the heme plane that is coupled to the displacement of myoglobin F-helix.

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