Revealing the origin of multiphasic dynamic behaviors in cyanobacteriochrome.
Proc Natl Acad Sci U S A
; 117(33): 19731-19736, 2020 08 18.
Article
em En
| MEDLINE
| ID: mdl-32759207
ABSTRACT
Cyanobacteriochromes are photoreceptors in cyanobacteria that exhibit a wide spectral coverage and unique photophysical properties from the photoinduced isomerization of a linear tetrapyrrole chromophore. Here, we integrate femtosecond-resolved fluorescence and transient-absorption methods and unambiguously showed the significant solvation dynamics occurring at the active site from a few to hundreds of picoseconds. These motions of local water molecules and polar side chains are continuously convoluted with the isomerization reaction, leading to a nonequilibrium processes with continuous active-site motions. By mutations of critical residues at the active site, the modified local structures become looser, resulting in faster solvation relaxations and isomerization reaction. The observation of solvation dynamics is significant and critical to the correct interpretation of often-observed multiphasic dynamic behaviors, and thus the previously invoked ground-state heterogeneity may not be relevant to the excited-state isomerization reaction.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Cianobactérias
/
Fotorreceptores Microbianos
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article