Following Ligand Migration Pathways from Picoseconds to Milliseconds in Type II Truncated Hemoglobin from Thermobifida fusca

CO recombination kinetics has been investigated in the type II truncated hemoglobin from Thermobifida fusca (Tf-trHb) over more than 10 time decades (from 1 ps to 100 ms) by combining femtosecond transient absorption, nanosecond laser flash photolysis and optoacoustic spectroscopy. Photolysis is fol...

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Detalhes bibliográficos
Autores: Marcelli, Agnese, Abbruzzetti, Stefania, Bustamante, Juan Pablo, Feis, Alessandro, Bonamore, Alessandra, Boffi, Alberto, Gellini, Cristina, Salvi, Pier R., Estrin, Dario Ariel, Bruno, Stefano, Viappiani, Cristiano, Foggi, Paolo
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2012
País:Argentina
Recursos:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/102682
Acesso em linha:http://hdl.handle.net/11336/102682
Access Level:acceso abierto
Palavra-chave:FLASH PHOTOLYSIS, TRANSIENT ABSORTION AND OPTOACOUSTIC SPECTROSCOPY
MOLECULAR DYNAMICS SIMULATIONS
LIGAND MIGRATION PATHWAYS
THERMOBIFIDA FUSCA TRUNCATED HEMOGLOBIN
https://purl.org/becyt/ford/1.4
https://purl.org/becyt/ford/1
Descrição
Resumo:CO recombination kinetics has been investigated in the type II truncated hemoglobin from Thermobifida fusca (Tf-trHb) over more than 10 time decades (from 1 ps to 100 ms) by combining femtosecond transient absorption, nanosecond laser flash photolysis and optoacoustic spectroscopy. Photolysis is followed by a rapid geminate recombination with a time constant of 2 ns representing almost 60% of the overall reaction. An additional, small amplitude geminate recombination was identified at 100 ns. Finally, CO pressure dependent measurements brought out the presence of two transient species in the second order rebinding phase, with time constants ranging from 3 to 100 ms. The available experimental evidence suggests that the two transients are due to the presence of two conformations which do not interconvert within the time frame of the experiment. Computational studies revealed that the plasticity of protein structure is able to define a branched pathway connecting the ligand binding site and the solvent. This allowed to build a kinetic model capable of describing the complete time course of the CO rebinding kinetics to Tf-trHb.

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