Spectroscopic properties of the carotenoid 3 '-hydroxyechinenone in the orange carotenoid protein from the cyanobacterium Arthrospira maxima
(2005) In Biochemistry 44(10). p.3994-4003- Abstract
- The cyanobacterial water-soluble orange carotenoid binding protein (OCP) is an ideal system for study of the effects of protein environment on photophysical properties of carotenoids. It contains a single pigment, the carotenoid 3'-hydoxyechinenone (hECN). In this study, we focus on spectroscopic properties of hECN in solution and in the OCP, aiming to elucidate the spectroscopic effects of the carotenoid-protein interaction in the context of the function(s) of the OCP. The noncovalent binding of hECN to the OCP causes a conformational change in the hECN, leading to a prolongation of the effective conjugation length. This change is responsible for shortening of the S, lifetime from 6.5 ps in solution to 3.3 ps in the OCP. The... (More)
- The cyanobacterial water-soluble orange carotenoid binding protein (OCP) is an ideal system for study of the effects of protein environment on photophysical properties of carotenoids. It contains a single pigment, the carotenoid 3'-hydoxyechinenone (hECN). In this study, we focus on spectroscopic properties of hECN in solution and in the OCP, aiming to elucidate the spectroscopic effects of the carotenoid-protein interaction in the context of the function(s) of the OCP. The noncovalent binding of hECN to the OCP causes a conformational change in the hECN, leading to a prolongation of the effective conjugation length. This change is responsible for shortening of the S, lifetime from 6.5 ps in solution to 3.3 ps in the OCP. The conformational change and the hydrogen bonding via the carbonyl group of hECN result in stabilization of an intramolecular charge-transfer (ICT) state. No signs of the ICT state were found in hECN in solution, regardless of the solvent polarity; spectral bands in transient absorption spectra of OCP-bound hECN exhibit features typical for the ICT state. Application of global fitting analysis revealed further effects of binding hECN in the OCP. The S, state of hECN in the OCP decays with two time constants of 0.9 and 3.3 ps. Modeling of the excited-state processes suggests that these two components are due to two populations of hECN in the OCP that differ in the hydrogen bonding via the carbonyl group. These results support the hypothesis that the OCP functions as a photoprotective shield under excess light. Mechanistically, the broadening of the hECN absorption spectrum upon binding to OCP enhances filtering, effect of hECN. Furthermore, the binding-induced conformational change and activation of the ICT state that leads to a shortening of hECN lifetime effectively makes the protein-bound hECN a more effective energy dissipator. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/151958
- author
- Polivka, Tomas LU ; Kerfeld, C A ; Pascher, Torbjörn LU and Sundström, Villy LU
- organization
- publishing date
- 2005
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Biochemistry
- volume
- 44
- issue
- 10
- pages
- 3994 - 4003
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- wos:000227629300034
- pmid:15751975
- scopus:14844347730
- pmid:15751975
- ISSN
- 0006-2960
- DOI
- 10.1021/bi047473t
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Chemical Physics (S) (011001060)
- id
- 7a5ad917-01f2-4f0a-af58-20c33eab014b (old id 151958)
- date added to LUP
- 2016-04-01 12:31:11
- date last changed
- 2022-03-29 01:57:23
@article{7a5ad917-01f2-4f0a-af58-20c33eab014b, abstract = {{The cyanobacterial water-soluble orange carotenoid binding protein (OCP) is an ideal system for study of the effects of protein environment on photophysical properties of carotenoids. It contains a single pigment, the carotenoid 3'-hydoxyechinenone (hECN). In this study, we focus on spectroscopic properties of hECN in solution and in the OCP, aiming to elucidate the spectroscopic effects of the carotenoid-protein interaction in the context of the function(s) of the OCP. The noncovalent binding of hECN to the OCP causes a conformational change in the hECN, leading to a prolongation of the effective conjugation length. This change is responsible for shortening of the S, lifetime from 6.5 ps in solution to 3.3 ps in the OCP. The conformational change and the hydrogen bonding via the carbonyl group of hECN result in stabilization of an intramolecular charge-transfer (ICT) state. No signs of the ICT state were found in hECN in solution, regardless of the solvent polarity; spectral bands in transient absorption spectra of OCP-bound hECN exhibit features typical for the ICT state. Application of global fitting analysis revealed further effects of binding hECN in the OCP. The S, state of hECN in the OCP decays with two time constants of 0.9 and 3.3 ps. Modeling of the excited-state processes suggests that these two components are due to two populations of hECN in the OCP that differ in the hydrogen bonding via the carbonyl group. These results support the hypothesis that the OCP functions as a photoprotective shield under excess light. Mechanistically, the broadening of the hECN absorption spectrum upon binding to OCP enhances filtering, effect of hECN. Furthermore, the binding-induced conformational change and activation of the ICT state that leads to a shortening of hECN lifetime effectively makes the protein-bound hECN a more effective energy dissipator.}}, author = {{Polivka, Tomas and Kerfeld, C A and Pascher, Torbjörn and Sundström, Villy}}, issn = {{0006-2960}}, language = {{eng}}, number = {{10}}, pages = {{3994--4003}}, publisher = {{The American Chemical Society (ACS)}}, series = {{Biochemistry}}, title = {{Spectroscopic properties of the carotenoid 3 '-hydroxyechinenone in the orange carotenoid protein from the cyanobacterium Arthrospira maxima}}, url = {{http://dx.doi.org/10.1021/bi047473t}}, doi = {{10.1021/bi047473t}}, volume = {{44}}, year = {{2005}}, }