In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 117, No. 33 ( 2020-08-18), p. 19731-19736
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.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.2001114117
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2020
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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