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Interaction of green tea or black tea polyphenols with protein in the presence or absence of other small ligands

Sun, Xiaowei
http://orcid.org/0000-0001-8654-8808
http://rave.ohiolink.edu/etdc/view?acc_num=miami1556296109059913

Abstract Details

2019, Doctor of Philosophy, Miami University, Cell, Molecular and Structural Biology (CMSB).
Polyphenols are important components of a variety of plant-based foods and drinks such as green tea, black tea, wine, chocolate and many fruits and fruit juices. It is widely reported that dietary polyphenols can reduce risk of many chronic diseases, such as Alzheimer’s disease, cancer, cardiovascular diseases and type 2 diabetes. Polyphenols are well-known for their activities as antioxidants, metal chelators and protein binding agents. The oxidative activity of polyphenols and their ability to bind metals could also be related to polyphenol-protein interaction. The interactions between polyphenols and proteins play an important role in human health, including pharmacological effects and bioavailability of epigallocatechin gallate (EGCg) in the circulatory system, and the fate of polyphenols in the oral cavity. The interaction between colored dietary polyphenols and salivary proteins is one of the main cause for the formation of the extrinsic tooth stain. To understand the biological fate of EGCg and the mechanism of persistent tooth stain, it is essential to investigate the nature of protein-polyphenol interaction with different modifiers under different conditions. We used several spectroscopic tools including FRET, circular dichroism, dynamic light scattering, as well as electrophoresis and MALDI-MS to investigate the interaction between the transport protein serum albumin and green tea EGCg in the presence and absence of palmitic acid. As a result, EGCg covalently binds to serum albumin possibly at Cys-471, Lys-437 and 455, and increases the inter-domain distance in serum albumin and palmitic bound serum albumin up to 3.4 angstrom and 4.05 angstrom, respectively. Moreover, palmitic acid has little effect, while EGCg decreases the serum albumin alpha-helix content in a dose-dependent fashion. We also used one or two tea cycle binding on hydroxyapatite (HA) to explore the fundamental mechanism of the ion-polyphenol-substrate interactions that lead to persistent tooth stains in the presence of mucin, black tea polyphenols, cationic antiseptics, and different metals. Our data support a model in which the surface of the HA is modified by the detergent CPC, which is tightly bound to the HA surface by ionic interactions with phosphate groups on the HA. CPC increases staining by both increasing the amount of polyphenol bound and by increasing the color of the polyphenols. Hard metals, particularly Al (III) (found in tea) and Sn (IV) tend to convert bound polyphenol complexes to irreversible forms, thus making the stain more difficult to remove from the HA surface.
Ann Hagerman (Advisor)
Rick Page (Committee Chair)
Carole Dabney-Smith (Committee Member)
Natosha Finley (Committee Member)
Andrea Kravats (Committee Member)
119 p.
Analytical Chemistry; Biochemistry; Biophysics
serum albumin; fatty acid; polyphenol; EGCg; protein conformation; protein aggregation; Forster resonance energy transfer; tooth stain; protein-polyphenol interaction

Recommended Citations

Citations

  • Sun, X. (2019). Interaction of green tea or black tea polyphenols with protein in the presence or absence of other small ligands [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1556296109059913

    APA Style (7th edition)

  • Sun, Xiaowei. Interaction of green tea or black tea polyphenols with protein in the presence or absence of other small ligands. 2019. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1556296109059913.

    MLA Style (8th edition)

  • Sun, Xiaowei. "Interaction of green tea or black tea polyphenols with protein in the presence or absence of other small ligands." Doctoral dissertation, Miami University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1556296109059913

    Chicago Manual of Style (17th edition)

miami1556296109059913
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© 2019, some rights reserved.Creative Commons License Interaction of green tea or black tea polyphenols with protein in the presence or absence of other small ligands by Xiaowei Sun is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Miami University and OhioLINK.