Novel aminoquinoline-based solvatochromic fluorescence probe: Interaction with albumin, lysozyme and characterization of amyloid fibrils

Author(s)

Pastrello, Bruna ^[1] ; dos Santos, Giovanny Carvalho ^[1] ; da Silva-Filho, Luiz Carlos ^[1] ; de Souza, Aguinaldo Robinson ^[1] ; Morgon, Nelson Henrique ^[2] ; Ximenes, Valdecir Farias ^[1]

Affiliation

^[1] UNESP Sao Paulo State Univ, Fac Sci, Dept Chem, BR-17033360 Bauru, SP - Brazil

^[2] Campinas State Univ UNICAMP, Inst Chem, Dept Phys Chem, BR-13083861 Campinas, SP - Brazil

• Document type: Journal article
• Source: DYES AND PIGMENTS; v. 173, FEB 2020.
• Web of Science Citations: 1

Abstract

A novel aminoquinoline derivative (AQ) was synthesized and applied as a solvatochromic fluorescent probe to study proteins and their alterations. AQ is not fluorescent in aqueous solution but has its fluorescence quantum yield significantly increased upon binding to albumin. The generation of an induced circular dichroism signal in AQ confirmed the complexation. The Job's plot method revealed an 1:1 stoichiometry for the host-guest complex. The binding constant was determined by AQ fluorescence increase (2.7 x 10(5) mol(-1) L) and by protein intrinsic fluorescence quenching (5.1 x 10(5) mol(-1) L). The displacement of AQ from albumin by warfarin and ibuprofen showed that Sudlow's drug site-I is the preferential binding site. By applying the Bilot-Kawski solvatochromic model to the spectral shifts of fifteen solvents, the microenvironment dielectric constant at albumin site-I was estimated (epsilon = 14.8). In agreement, the average fluorescence lifetime of AQ complexed with albumin (6.11 ns) was close to dichloromethane (6.53 ns) and acetone (6.34 ns), which have dielectric constants of 8.9 and 21.0, respectively. Albumin was thermically treated to formation of amyloid fibril aggregates. AQ was able to differentiate the altered and native protein. Sodium dodecyl sulfate-induced aggregation of lysozyme to amyloid fibril was also efficiently detected by the AQ fluorescence increase. AQ was as efficient as the chromogenic bromocresol purple in the quantitative analysis of albumin. In conclusion, AQ can be considered a new solvatochromic fluorescent probe with several potential applications. (AU)

• FAPESP's process: 15/00615-0 - Studies on the synthesis and photochemical and photophysical characterization of quinoline derivatives with donor-p-acceptor structure for use as sensitizing dyes in organic electronic devices
• Grantee: Giovanny Carvalho dos Santos
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 15/22338-9 - Study of the interaction between drugs and human serum albumin (HSA) based on computer simulation, DFT and TDDFT, experiments of electronic circular dichroism, ECD, and determination of the bond formation constant
• Grantee: Aguinaldo Robinson de Souza
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/20549-5 - Development and application of fluorescent probes and probes based on circular dichroism for the interaction studies of ligands with protein, characterization of amyloid proteins and determination of enzymatic activity
• Grantee: Valdecir Farias Ximenes
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/14506-7 - Study about the one-pot synthesis and application as organic dyes of quinolone and anthrazoline derivatives
• Grantee: Luiz Carlos da Silva Filho
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/50926-0 - INCT 2014: biodiversity and natural products
• Grantee: Vanderlan da Silva Bolzani
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants