UV Excitation of Carotenoid Binding Proteins OCP and HCP: Excited-State Dynamics and Product Formation

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60076658%3A12310%2F22%3A43904805" target="_blank" >RIV/60076658:12310/22:43904805 - isvavai.cz</a>
Result on the web
<a href="https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/cptc.202100194" target="_blank" >https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/cptc.202100194</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1002/cptc.202100194" target="_blank" >10.1002/cptc.202100194</a>

Result language
angličtina
Original language name
UV Excitation of Carotenoid Binding Proteins OCP and HCP: Excited-State Dynamics and Product Formation
Original language description
Over the last decade the orange carotenoid protein (OCP) gained attention due to its role in photoprotection in cyanobacteria. Recently, other carotenoid binding proteins such as helical carotenoid proteins (HCPs) have been identified and characterized, although the function of the HCPs is not yet clarified. Here we have examined OCP1 and two HCPs, HCP2 and HCP3, from Tolypothrix PCC 7601 by ultrafast spectroscopy after excitation of both carotenoid canthaxanthin and amino acids tryptophan and tyrosine in UV at 275 nm. We find that the canthaxanthin S-1 lifetime remains the same 3.5 ps as for excitation of the carotenoid S-2 state, but the S* signal is significantly amplified by UV excitation. In contrast to the S-2 excitation, we observe a formation of the canthaxanthin radical cation at 900 nm for all three proteins after 275 nm excitation. In OCP1, UV light also enhances the amplitude of spectral band centered at 550 nm at longer delays. This band likely corresponds to the first photoproduct of the OCP photocycle, suggesting that excess energy excitation and/or direct excitation of amino acids can enhance the product formation.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10610 - Biophysics

Project
<a href="/en/project/GX19-28323X" target="_blank" >GX19-28323X: Relation between structure and function of carotenoids: New pathways to answer unresolved questions</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2022
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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