Albumin-induced circular dichroism in Congo red: Applications for studies of amyloid-like fibril aggregates and binding sites

Vasconcelos, Débora Naliati de; Ximenes, Valdecir Farias

doi:10.1016/j.saa.2015.05.089

Cited by 21 publications

(15 citation statements)

References 43 publications

(65 reference statements)

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“…This is the case of studies focused on the determination of binding characteristics of potential ligands with albumins . In this regard, bovine serum albumin (BSA) has been applied in numerous studies involving different ligands; and fluorescence quenching is the usual physicochemical approach to study these interactions . BSA is used as a model protein to study the interaction between drugs and albumins .…”

Section: Introductionmentioning

confidence: 99%

Entropy‐driven binding of octyl gallate in albumin: Failure in the application of temperature effect to distinguish dynamic and static fluorescence quenching

Bertozo

Fernandes

Yoguim

et al. 2020

J of Molecular Recognition

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Fluorescence quenching is widely used to obtain association constants between proteins and ligands. This methodology is based on assumption that ground-state complex between protein and ligand is responsible for quenching. Here, we call the attention about the risk of using the temperature criterion for decision of applying or not fluorescence quenching data to measure association constants. We demonstrated that hydrophobic effect can be the major force involved in the interaction and, as such, superposes the well-established rationalization that host/guest com-

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Section: Introductionmentioning

confidence: 99%

Entropy‐driven binding of octyl gallate in albumin: Failure in the application of temperature effect to distinguish dynamic and static fluorescence quenching

Bertozo

Fernandes

Yoguim

et al. 2020

J of Molecular Recognition

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“…In fact, the capacity of CR to inhibit A β aggregation has led to its study as a therapeutic agent for amyloid fibril‐related diseases such as Alzheimer's disease . Interestingly, CR exhibits enhanced fluorescence and/or induced optical activity (circular dichroism) when bound to amyloid fibrils, synthetic peptides, poly( l ‐lysine), enzymes and proteins . CR readily forms complexes with other materials such as cellulose fibers, the polysaccharide grifolan, poly(vinyl alcohol) hydrogels, graphite oxide, and has been incorporated into polymer films and capsules .…”

Section: Introductionmentioning

confidence: 99%

Insights into the Photophysics and Supramolecular Organization of Congo Red in Solution and the Solid State

et al. 2017

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Steady-state and time-resolved absorption and fluorescence measurements are reported for Congo Red (CR) in aqueous and dimethylsulfoxide (DMSO) solutions. The very low fluorescence quantum yield (≈10 ) for CR in dilute solutions together with the absence of a triplet state indicates that internal conversion is the dominant deactivation route with more than 99.99 % of the quanta loss (attributed to the energy gap law for radiationless transitions). Although no direct evidence for trans-cis photoisomerization was obtained from absorption or fluorescence data, the global analysis of fs-transient absorption data indicates the presence of a photoproduct with a lifetime of ≈170 ps that is suggested to be associated with such a process. Spectral data for more concentrated CR solutions indicate the presence of oblique or twisted J-type aggregates. These results are compared with spectra for CR in the solid state (sodium salt) and intercalated in a layered double hydroxide via a one-step co-precipitation route. Powder XRD and electronic spectral data for the nanohybrid indicate that the CR guest molecules are intercalated as a monolayer consisting of slipped cofacial J-type aggregates.

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“…The ICD was used to monitor the displacement of divanillin from the its binding sites in BSA using well-accepted pharmaceutical drugs that are specific ligands for site I (phenylbutazone and warfarin) and for site II (naproxen and ibuprofen). The experimental condition was equimolar amounts of BSA:divanillin (30 μmol L -1 ) and increasing amounts of the drugs (0–90 μmol L -1 ) [ 35 ].…”

Section: Methodsmentioning

confidence: 99%

Induction of axial chirality in divanillin by interaction with bovine serum albumin

et al. 2017

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Vanillin is a plant secondary metabolite and has numerous beneficial health applications. Divanillin is the homodimer of vanillin and used as a taste enhancer compound and also a promissory anticancer drug. Here, divanillin was synthesized and studied in the context of its interaction with bovine serum albumin (BSA). We found that divanillin acquires axial chirality when complexed with BSA. This chiroptical property was demonstrated by a strong induced circular dichroism (ICD) signal. In agreement with this finding, the association constant between BSA and divanillin (3.3 x 105 mol-1L) was higher compared to its precursor vanillin (7.3 x 104 mol-1L). The ICD signal was used for evaluation of the association constant, demonstration of the reversibility of the interaction and determination of the binding site, revealing that divanillin has preference for Sudlow’s site I in BSA. This property was confirmed by displacement of the fluorescent markers warfarin (site I) and dansyl-L-proline (site II). Molecular docking simulation confirmed the higher affinity of divanillin to site I. The highest scored conformation obtained by docking (dihedral angle 242°) was used for calculation of the circular dichroism spectrum of divanillin using Time-Dependent Density Functional Theory (TDDFT). The theoretical spectrum showed good similarity with the experimental ICD. In summary, we have demonstrated that by interacting with the chiral cavities in BSA, divanillin became a atropos biphenyl, i.e., the free rotation around the single bound that links the aromatic rings was impeded. This phenomenon can be explained considering the interactions of divanillin with amino acid residues in the binding site of the protein. This chiroptical property can be very useful for studying the effects of divanillin in biological systems. Considering the potential pharmacological application of divanillin, these findings will be helpful for researchers interested in the pharmacological properties of this compound.

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Albumin-induced circular dichroism in Congo red: Applications for studies of amyloid-like fibril aggregates and binding sites

Cited by 21 publications

References 43 publications

Entropy‐driven binding of octyl gallate in albumin: Failure in the application of temperature effect to distinguish dynamic and static fluorescence quenching

Entropy‐driven binding of octyl gallate in albumin: Failure in the application of temperature effect to distinguish dynamic and static fluorescence quenching

Insights into the Photophysics and Supramolecular Organization of Congo Red in Solution and the Solid State

Induction of axial chirality in divanillin by interaction with bovine serum albumin

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