title: Conformational alterations induced by novel green 16-E2-16 gemini surfactant in xanthine oxidase: Biophysical insights from tensiometry, spectroscopy, microscopy and molecular modeling.
abstract: Herein we report the interaction of a biodegradable gemini surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy) dichloride (16-E2-16) with bovine milk xanthine oxidase (XO), employing tensiometry, fluorescence spectroscopy, UV spectroscopy, far-UV circular dichroism spectroscopy (CD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and computational molecular modeling. Surface tension results depict substantial changes in the micellar as well as interfacial parameters (CMC, ΠCMC, γCMC, Γmax, Amin, ΔGmic° and ΔGads°) of 16-E2-16 gemini surfactant upon XO combination, deciphering the interaction of XO with the gemini surfactant. Fluorescence measurements reveal that 16-E2-16 gemini surfactant causes quenching in the xanthine oxidase (XO) fluorescence spectra via static procedure and the values of various evaluated binding parameters (KSV, Kb, kq, ΔGb° and n) describe that 16-E2-16 effectively binds to XO. Three dimensional fluorescence, 8-anilino-1-naphthalene sulfonic acid (ANS) binding, F1F3 ratio, UV, CD, FTIR, SEM and TEM results delineate changes in the secondary structure of xanthine oxidase. Molecular docking results provide complement to the steady-state fluorescence findings and support the view that quenching occurs due to non-polar environment experienced by aromatic residues of the enzyme. The results of this study can help scientists to tune the conformation of an enzyme (XO) with biocompatible amphiphilic microstructures, which will help to unfold further understanding in the treatment modes of various diseases like gout, hyperuricemia, liver and brain necrosis.
authors.affiliation: Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India. Electronic address: drmohdakram@rediffmail.com.
authors.forename: Mohd
authors.initials: M
authors.lastname: Akram
authors.affiliation: Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India.
authors.forename: Imtiyaz Ahmad
authors.initials: IA
authors.lastname: Bhat
authors.affiliation: Department of Biochemistry, Aligarh Muslim University, Aligarh 202002, India.
authors.forename: Waseem Feeroze
authors.initials: WF
authors.lastname: Bhat
authors.affiliation: Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India.
authors.lastname: Kabir-ud-Din
mesh_terms: D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D008853:Microscopy / Q000379:methods; D008958:Models, Molecular; D008968:Molecular Conformation / Q000187:drug effects*; D017433:Protein Structure, Secondary; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry / Q000494:pharmacology*; D014969:Xanthine Oxidase / Q000737:chemistry* / Q000187:drug effects*
chemical_list: C000610348:16-E2-16 gemini surfactant; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D014969:Xanthine Oxidase; D005998:Glycine
keywords: Docking; Fluorescence quenching; Gemini surfactant; Xanthine oxidase