Simultaneous binding of folic acid and lutein to ?-lactoglobulin and ?-lactalbumin: A spectroscopic and molecular docking study

Author(s)

Vidotto, Danilo C. ; Tavares, Guilherme M.

• Document type: Journal article
• Source: FOOD BIOSCIENCE; v. 50, p. 9-pg., 2022-12-01.

Abstract

Whey proteins are versatile molecules with great nutritional value and multiple functionalities. One of these functionalities is the ability to bind and protect bioactive compounds. Lutein and folic acid (FA) are bioactive molecules with a remarkable relevance for developing functional foods. FA contributes in preventing the occurrence of neural tube defects during the early stages of life, while lutein is a macular pigment that contributes to the development of the retina. In this context, the aim of this work was to evaluate the ability of the main whey proteins, beta-lactoglobulin and alpha-lactalbumin, to simultaneously bind FA and lutein. The binding was evaluated through intrinsic fluorescence quenching and molecular docking, and the impact of the binding on the secondary structure and denaturation temperature of the proteins were also evaluated through circular dichroism and differential scanning calorimetry, respectively. Both proteins had similar behavior on the performed analyses. The multi-binding ability of beta-lactoglobulin and alpha-lactalbumin to FA and lutein was observed. The presence of the first ligand slightly reduced the association constant between the second one and the proteins; in particular for the binding of lutein in the presence of FA (reduction of around 36%-38% on the KSV values). Molecular docking indicated that both ligands interact, preferentially, on the same region of the studied protein structures. The secondary structure of the proteins, as well as their denaturation temperatures were minimally impacted by the presence of these ligands, themselves. Our results may contribute to the development of multi-functional protein-rich food products. (AU)

• FAPESP's process: 18/03822-5 - Multi-user equipment approved in grant 2017/09214-4: preparative chromatography system - Akta pure (Ge healthcare)
• Grantee: Guilherme Miranda Tavares
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 17/09214-4 - How do structural changes of dairy proteins affect the functionality of bioactive compounds in complex food matrices?
• Grantee: Guilherme Miranda Tavares
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 18/09304-6 - Interaction between carotenoids and native and non-native globular proteins from milk: structural and functional effects in mono and multi protein systems
• Grantee: Danilo Corsi Vidotto
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 18/23752-1 - Multi0user equipment approved in grant 2013/07914-8: high-speed liquid chromatography coupled to arrangement of diodes, fluorescence and masses
• Grantee: Adriana Zerlotti Mercadante
• Support Opportunities: Multi-user Equipment Program