Intrinsic tryptophan fluorescence quenching by iodine in non-canonical amino acid reveals alteration of the hydrogen bond network in the photoactive orange carotenoid protein.

Autor: Tsoraev GV; Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia., Bukhanko AY; Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia., Mamchur AA; Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia., Yaroshevich IA; Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia., Sluchanko NN; A.N. Bach Institute of Biochemistry, Federal Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia., Tseng HW; Technical University of Berlin, Institute of Chemistry PC 14, Straße des 17. Juni 135, 10623, Berlin, Germany., Moldenhauer M; Technical University of Berlin, Institute of Chemistry PC 14, Straße des 17. Juni 135, 10623, Berlin, Germany., Budisa N; Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada., Friedrich T; Technical University of Berlin, Institute of Chemistry PC 14, Straße des 17. Juni 135, 10623, Berlin, Germany., Maksimov EG; Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia. Electronic address: emaksimoff@yandex.ru.
Jazyk: angličtina
Zdroj: Biochemical and biophysical research communications [Biochem Biophys Res Commun] 2023 Nov 26; Vol. 683, pp. 149119. Date of Electronic Publication: 2023 Oct 14.
DOI: 10.1016/j.bbrc.2023.10.051
Abstrakt: The Orange Carotenoid Protein (OCP) regulates cyanobacterial photosynthetic activity through photoactivation in intense light. A hydrogen bonding network involving the keto-carotenoid oxygen and Y201 and W288 residues prevents the spontaneous activation of dark-adapted OCP. To investigate the role of the hydrogen bonds in OCP photocycling, we introduced non-canonical amino acids near the keto-carotenoid, particularly iodine at the meta-position of Y201. This modification significantly increased the yield of red OCP photoproducts, albeit with a shorter lifetime. Changes in tryptophan fluorescence during photocycling influenced by the presence of iodine near W288 revealed interactions between Y201 and W288 in the absence of the carotenoid in the C-domain. We propose that upon the relaxation of red states, a ternary complex with the carotenoid is formed. Analysis of spectral signatures and interaction energies indicates that the specific iodo-tyrosine configuration enhances interactions between the carotenoid and W288.
Competing Interests: Declaration of competing interest Authors declare no conflict of interest.
(Copyright © 2023 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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