Affordable Access

deepdyve-link
Publisher Website

Quercetin-induced inactivation and conformational alterations of alpha-2-macroglobulin: multi-spectroscopic and calorimetric study.

Authors
  • Siddiqui, Tooba1
  • Zia, Mohammad Khalid1
  • Ahsan, Haseeb2
  • Khan, Fahim Halim1
  • 1 Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, India. , (India)
  • 2 Department of Biochemistry, Faculty of Dentistry, Jamia Millia Islamia, New Delhi, India. , (India)
Type
Published Article
Journal
Journal of biomolecular structure & dynamics
Publication Date
Sep 01, 2020
Volume
38
Issue
14
Pages
4107–4118
Identifiers
DOI: 10.1080/07391102.2019.1671232
PMID: 31543004
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

Quercetin is a widely used bioflavonoid found in onions, grapes, berries and citrus fruits. Under certain conditions, quercetin acts as a pro-oxidant thereby generating reactive oxygen species and promoting the oxidation of molecules. Our study investigates the effect of quercetin on the structure and function of alpha-2-macroglobulin (α2M) by employing various biophysical techniques and trypsin inhibitory assay. α2M is the major antiproteinase present in the plasma of vertebrates. Results of activity assay indicated that α2M loses its 56% of inhibitory activity on treatment with quercetin in the presence of light. UV spectroscopy reveals hyper chromaticity in absorption spectra of protein on interaction with quercetin suggesting structural change. The intrinsic fluorescence studies showed quenching of α2M spectra in the presence of quercetin, and the mode of quenching was found to be static in nature. Synchronous fluorescence indicated the alteration in the microenvironment of tryptophan residues. CD and FTIR spectroscopy confirms concentration-dependent alterations in secondary structure of α2M instigated by quercetin. The magnitude of binding constant, enthalpy change, entropy change and free energy change during the interaction process was determined by isothermal titration calorimetry. Hydrogen bonding and hydrophobic interaction were the main intermolecular forces involved during the process. This study identifies and signifies the damage induced by quercetin to α2M due to its pro-oxidant action. Communicated by Ramaswamy H. Sarma.

Report this publication

Statistics

Seen <100 times