Carotenoid-protein interaction alters the S1 energy of hydroxyechinenone in the Orange Carotenoid Protein

0395026 - BC 2014 RIV NL eng J - Journal Article
Polívka, Tomáš - Chábera, P. - Kerfeld, C.A.
Carotenoid-protein interaction alters the S1 energy of hydroxyechinenone in the Orange Carotenoid Protein.
Biochimica Et Biophysica Acta-Bioenergetics. Roč. 1827, č. 3 (2013), s. 248-254. ISSN 0005-2728. E-ISSN 1879-2650
Institutional support: RVO:60077344
Keywords : orange-carotenoid protein * excited states * photoprotection
Subject RIV: BO - Biophysics
Impact factor: 4.829, year: 2013

We have determined the S1 energy of the carotenoid hydroxyechinenone (hECN) in organic solvent and compared it with the S1 energy of hECN bound to the OCP. In methanol and n-hexane, hECN has an S1 energy of 14,300 cm-1, slightly higher than carotenoids with shorter conjugation lengths such as zeaxanthin or beta-carotene; this is consistent with the proposal that the presence of the conjugated carbonyl group in hECN increases its S1 energy. Upon binding to the OCP, the S1 energy of hECN is further increased to 14,700 cm-1, underscoring the importance of protein binding which twists the conjugated carbonyl group into s-trans conformation and enhances the effect of the carbonyl group. Activated OCP, however, has an S1 energy of 14,000 cm-1, indicating that significant changes in the vicinity of the conjugated carbonyl group occur upon activation.
Permanent Link: http://hdl.handle.net/11104/0223199