Covalent binding of food-derived blue pigment phycocyanobilin to bovine beta-lactoglobulin under physiological conditions
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2018
Authors
Minic, SimeonRadomirović, Mirjana

Savkovic, Nina
Radibratović, Milica

Mihailović, Jelena

Vasovic, Tamara
Nikolić, Milan

Milčić, Miloš

Stanić-Vučinić, Dragana

Ćirković Veličković, Tanja

Article (Published version)

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Show full item recordAbstract
In this study, we investigated structural aspects of covalent binding of food derived blue pigment phycocyanobilin (PCB) to bovine beta-lactoglobulin (BLG), major whey protein, by spectroscopic, electrophoretic, mass spectrometry and computational methods. At physiological pH (7.2), we found that covalent pigment binding via free cysteine residue is slow (k(a)=0.065 min(-1)), of moderate affinity (K-a=4x10(4) M-1), and stereo-selective. Binding also occurs at a broad pH range and under simulated gastrointestinal conditions. Adduct formation rises with pH, and in concentrated urea (k(a)=0.101 min(-1)). The BLG-PCB adduct has slightly altered secondary and tertiary protein structure, and bound PCB has higher fluorescence and more stretched conformation than free chromophore. Combination of steered molecular dynamic for disulfide exchange, non-covalent and covalent docking, favours Cys119 residue in protein calyx as target for covalent BLG-PCB adduct formation. Our results suggest that th...is adduct can serve as delivery system of bioactive PCB.
Keywords:
beta-lactoglobulin / Phycocyanobilin / Phycocyanin / Covalent / Binding / Spirulina / Fluorescence / Molecular dockingSource:
Food Chemistry, 2018, 269, 43-52Publisher:
- Elsevier Sci Ltd, Oxford
Projects:
- Molecular properties and modifications of some respiratory and nutritional allergens (RS-172024)
- Reinforcement of the Faculty of Chemistry, University of Belgrade, towards becoming a Center of Excellence in the region of WB for Molecular Biotechnology and Food research (EU-256716)
Note:
- The peer-reviewed version: http://cer.ihtm.bg.ac.rs/handle/123456789/3022
DOI: 10.1016/j.foodchem.2018.06.138
ISSN: 0308-8146
PubMed: 30100456