o:34421 Investigation of the Potential of Selected Food-Derived Antioxidants to Bind and Stabilise the Bioactive Blue Protein C-Phycocyanin from Cyanobacteria Spirulina Ispitivanje mogućnosti odabranih antioksidanata iz hrane da se vežu i stabilizuju bioaktivni plavi proteini C-Fikocijanin iz cijanobakterije Spiruline en ABSTRACT Blue C-phycocyanin (C-PC), the major Spirulina protein with innumerable health-promoting benefits, is an attractive colourant and food supplement. A crucial obstacle to its more extensive use is its relatively low stability. This study aimed to screen various food-derived ligands for their ability to bind and stabilise C-PC, utilising spectroscopic techniques and molecular docking. Among twelve examined ligands, the protein fluorescence quenching revealed that only quercetin, coenzyme Q10 and resveratrol had a moderate affinity to C-PC (Ka of 2.2 to 3.7 × 105 M–1). Docking revealed these three ligands bind more strongly to the C-PC hexamer than the trimer, with the binding sites located at the interface of two (αβ)3 trimers. UV/VIS absorption spectroscopy demonstrated the changes in the C-PC absorption spectra in a complex with quercetin and resveratrol compared to the spectra of free protein and ligands. Selected ligands did not affect the secondary structure content, but they induced changes in the tertiary protein structure in the CD study. A fluorescence-based thermal stability assay demonstrated quercetin and coenzyme Q10 increased the C-PC melting point by nearly 5 °C. Our study identified food-derived ligands that interact with C-PC and improve its thermal stability, indicating their potential as stabilising agents for C-PC in the food industry. C-phycocyanin; spirulina; food antioxidants; quercetin; resveratrol; coenzyme Q10; binding interactions; spectroscopic methods; molecular docking; protein stabilisation 1552099 10.3390/ijms25010229 2024-08-13T07:05:30.263Z 44 yes 46 Nikola Gligorijević University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Chemistry, National Institute of the Republic of Serbia, Belgrade, Serbia Zorana Jovanović University of Belgrade, Faculty of Chemistry, Center of Excellence for Molecular Food Sciences & Department of Biochemistry, Belgrade, Serbia person Ilija Cvijetić University of Belgrade, Faculty of Chemistry, Department of Analytical Chemistry, Belgrade, Serbia person Miloš Šunderić University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor biohemijskih nauka person 0000-0002-0940-9481 Luka Veličković University of Belgrade, Faculty of Chemistry, Center of Excellence for Molecular Food Sciences & Department of Biochemistry, Belgrade, Serbia person Jaroslav Katrlik Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia person Alena Holazova Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia person Milan Nikolić University of Belgrade, Faculty of Chemistry, Center of Excellence for Molecular Food Sciences & Department of Biochemistry, Belgrade, Serbia person Simeon Minić University of Belgrade, Faculty of Chemistry, Center of Excellence for Molecular Food Sciences & Department of Biochemistry, Belgrade, Serbia person application/pdf 3588143 https://phaidrabg.bg.ac.rs/o:34421 no yes 18 70 92000001 11A24 11A2404 11A19 11A1904 11A29 11A2905 International Journal of Molecular Sciences 25 1 229 MDPI 2024