Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 36
Filter
Add more filters










Publication year range
1.
J Pharm Biomed Anal ; 233: 115448, 2023 Sep 05.
Article in English | MEDLINE | ID: mdl-37167767

ABSTRACT

The molecular docking calculations have been employed to investigate the interactions a set of proteins with the repurposed anti-COVID drugs. The position of the therapeutic agents within the protein structure was dependent on a particular drug-protein system and varied from the binding cleft to the periphery of the polypeptide chain. Interactions involved in the drug-protein complexation includes predominantly hydrogen bonding and hydrophobic contacts. The obtained results may be of particular importance while developing the anti-COVID strategies as well as for deeper understanding of the drug pharmacodynamics and pharmacokinetics.


Subject(s)
Antiviral Agents , COVID-19 , Humans , Antiviral Agents/therapeutic use , SARS-CoV-2 , Molecular Docking Simulation , Molecular Dynamics Simulation
2.
BBA Adv ; 2: 100059, 2022.
Article in English | MEDLINE | ID: mdl-37082586

ABSTRACT

The Förster resonance energy transfer (FRET) is a well-established and versatile spectroscopic technique extensively used for exploring a variety of biomolecular interactions and processes. The present review is intended to cover the main results of our FRET studies focused on amyloid fibrils, a particular type of disease-associated protein aggregates. Based on the examples of several fibril-forming proteins including insulin, lysozyme and amyloidogenic variants of N-terminal fragment of apolipoprotein A-I, it was demonstrated that: (i) the two- and three-step FRET with the classical amyloid marker Thioflavin T as an input donor has a high amyloid-sensing potential and can be used to refine the amyloid detection assays; (ii) the intermolecular time-resolved and single-molecule pulse interleaved excitation FRET can give quantitative information on the nucleation of amyloid fibrils; (iii) FRET between the membrane fluorescent probes and protein-associated intrinsic or extrinsic fluorophores is suitable for monitoring the membrane binding of fibrillar proteins, exploring their location relative to lipid-water interface and restructuring on a lipid matrix; (iv) the FRET-based distance estimation between fibril-bound donor and acceptor fluorophores can serve as one of the verification criteria upon structural modeling of amyloid fibrils.

3.
Phys Chem Chem Phys ; 23(27): 14746-14754, 2021 Jul 14.
Article in English | MEDLINE | ID: mdl-34195724

ABSTRACT

The present study provides evidence that the energy transfer chain consisting of the benzothiazole dye Thioflavin T as an input donor, a phosphonium dye TDV and a squaraine dye SQ4 as mediators, and one of the three squaraines SQ1/2/3 as an output acceptor displays an excellent amyloid-sensing ability when applied to differentiating between the amyloid and non-fibrillized states of insulin. The ensemble of fluorophores offers the advantages of a large effective Stokes shift (∼240 nm), well-resolved 3D fluorescence patterns and strong enhancement of the terminal fluorescence (up to two orders of magnitude). The occurrence of multistep energy transfer on an amyloid fibril scaffold opens new possibilities for the more sensitive detection of fibrillar protein assemblies and their applications in nanophotonics.


Subject(s)
Amyloid/chemistry , Fluorescent Dyes/chemistry , Benzothiazoles , Fluorescence Resonance Energy Transfer , Kinetics , Molecular Docking Simulation , Protein Binding , Protein Conformation , Protein Multimerization , Structure-Activity Relationship
4.
J Fluoresc ; 31(4): 1065-1073, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33956266

ABSTRACT

This study is devoted to the development of a methodological approach to mathematical analysis and data interpretation of blood serum phosphorescence intensity in cancer patients for determining the pathological states and differential diagnostics of oncological process stages. The purpose of the study is blood serum phosphorescence research in patients with colorectal cancer (CRC) and stomach adenocarcinoma (SAC) and determination of the ultraweak luminescence role for diagnostics of the disease, determining its stages, control of pathogenetic therapy efficiency and forecast of recovery. The values of phosphorescence intensity of blood serum films in patients with CRC and SAC are significantly higher than the corresponding values for the control group. Contrary to the absolute intensity, the relative intensity increase compared to the control group is much more informative for oncoprocess diagnostics, since it exhibits three times increase even at the first stage of tumoral process. Serum phosphorescence intensity continues to increase with progressing of the disease. As the result of our study, the relative intensity increase compared to the first stage can be recommended as an informative indicator for differential diagnostics of oncological process stages. As a conclusion, determination of blood serum phosphorescence intensity can be considered as a sensitive and specific diagnostic method in oncology. With a correct methodological approach to data processing and interpretation, this method can be used in clinical practice for determining the oncopathological states, differential diagnostics of oncoprocess stages and diagnostics of precancer changes, which precede tumoral process development.


Subject(s)
Luminescent Measurements , Humans , Neoplasms
5.
Luminescence ; 36(3): 795-801, 2021 May.
Article in English | MEDLINE | ID: mdl-33398923

ABSTRACT

Molecular interactions between novel europium coordination complexes (EC) possessing superior cytotoxic activity and bovine serum albumin (BSA), the most prominent representative of plasma proteins, were assessed using fluorescence spectroscopy and molecular docking techniques. Cumulative results from fluorescent probe binding, fluorescence quenching and Förster resonance energy transfer studies revealed that the europium complexes V4 and V8 do not perturb the BSA structure, while V3, V5, and V7 induce partial unfolding of the polypeptide chain. Molecular docking studies coupled with analysis of the three-dimensional structure of the BSA-EC complexes showed that V4 and V8 reside in the vicinity of the protein IIA subdomain (Sudlow's site I), while V3, V5 and V5 were localized predominantly in the BSA IIIA subdomain (Sudlow's site II). Due to the intactness of the protein structure upon association with V4 and V8, these compounds may be recommended for further evaluation as potential antineoplastic agents.


Subject(s)
Coordination Complexes , Serum Albumin , Binding Sites , Europium , Molecular Docking Simulation , Protein Binding , Serum Albumin/metabolism , Serum Albumin, Bovine/metabolism , Spectrometry, Fluorescence , Thermodynamics
6.
J Fluoresc ; 28(5): 1037-1047, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30008060

ABSTRACT

The effects of one of the amyloidogenic mutations of apolipoprotein A-I (apoA-I), G26R, on the thermal stability, structural dynamics and lipid-associating properties of the 1-83 N-terminal fragment of apoA-I (A83) have been investigated using the Förster resonance energy transfer (FRET) and molecular dynamics (MD) simulation. The measurements of FRET between the tryptophan residues of the single Trp variants of A83 as donors and the membrane-incorporated fluorescent probe 4-dimethylaminochalcone as an acceptor provided evidence for a less depth of A83/G26R penetration into phosphatidylcholine (PC) bilayer compared to WT counterpart. The unfolding MD simulations showed that G26R mutation destabilizes the overall structure of A83, with individual alpha-helices differing in their thermal stability. The MD simulations performed at physiological temperature revealed that A83 and A83/G26R differ in their conformational behavior in an aqueous solution, PC and PC/Cholesterol bilayers. These findings may prove of importance for deeper understanding of the key determinants of apoA-I amyloidogenesis.


Subject(s)
Apolipoprotein A-I/chemistry , Fluorescence Resonance Energy Transfer , Lipid Bilayers/chemistry , Molecular Dynamics Simulation , Peptide Fragments/chemistry , Apolipoprotein A-I/genetics , Fluorescent Dyes/chemistry , Humans , Mutation
7.
J Fluoresc ; 28(1): 79-88, 2018 Jan.
Article in English | MEDLINE | ID: mdl-28879486

ABSTRACT

Specific interactions between a mitochondrial hemoprotein cytochrome c (cyt c) and cardiolipin, a lipid component of mitochondrial membrane, are crucial to electron shuttling and apoptotic activities of this protein. In the present study the Förster resonance energy transfer (FRET) between anthrylvinyl-labeled phosphatidylcholine as a donor and heme moiety of cyt c as an acceptor was employed to give a quantitative characterization of the protein binding to the model membranes from the mixtures of phosphatidylcholine (PC) with phosphatidylglycerol (PG), phosphatidylserine (PS) or cardiolipin (CL) in different molar ratios. The multiple arrays of the FRET data were globally analyzed in terms of the model of energy transfer in two-dimensional systems combined with the scaled particle adsorption model. The arguments in favor of the specificity of cyt c interactions with CL were obtained, including the higher adsorption potential and the deeper protein insertion in the lipid bilayer.


Subject(s)
Cardiolipins/metabolism , Cytochromes c/metabolism , Fluorescence Resonance Energy Transfer/methods , Lipid Bilayers/metabolism , Phosphatidylcholines/metabolism , Phosphatidylglycerols/metabolism , Phosphatidylserines/metabolism , Animals , Cardiolipins/chemistry , Cytochromes c/chemistry , Horses , Kinetics , Lipid Bilayers/chemistry , Phosphatidylcholines/chemistry , Phosphatidylglycerols/chemistry , Phosphatidylserines/chemistry , Protein Binding , Spectrometry, Fluorescence
8.
J Biomol Struct Dyn ; 36(9): 2249-2260, 2018 Jul.
Article in English | MEDLINE | ID: mdl-28665188

ABSTRACT

Using the molecular dynamics simulation, the role of lipids in the lysozyme transition into the aggregation-competent conformation has been clarified. Analysis of the changes of lysozyme secondary structure upon its interactions with the model bilayer membranes composed of phosphatidylcholine and its mixtures with phosphatidylglycerol (10, 40, and 80 mol%) within the time interval of 100 ns showed that lipid-bound protein is characterized by the increased content of ß-structures. Along with this, the formation of protein-lipid complexes was accompanied by the increase in the gyration radius and the decrease in RMSD of polypeptide chain. The results obtained were interpreted in terms of the partial unfolding of lysozyme molecule on the lipid matrix, with the magnitude of this effect being increased with increasing the fraction of anionic lipids. Based on the results of molecular dynamics simulation, a hypothetical model of the nucleation of lysozyme amyloid fibrils in a membrane environment was suggested.


Subject(s)
Lipids/chemistry , Molecular Dynamics Simulation , Muramidase/chemistry , Amyloid/chemistry , Animals , Lipid Bilayers/chemistry , Muramidase/metabolism , Protein Aggregates , Protein Binding , Protein Conformation , Proteins/chemistry , Proteins/metabolism
9.
Mol Biosyst ; 13(5): 970-980, 2017 May 02.
Article in English | MEDLINE | ID: mdl-28379242

ABSTRACT

Two newly synthesized symmetrical heptamethine cyanine dyes, AK7-5 and AK7-6, absorbing in the region of low autofluorescence of biological samples, have been tested for their ability to detect proteins aggregated into amyloid fibrils. In aqueous solution these probes possess three absorption bands corresponding to the monomer, dimer and H-aggregate species. The association of the dye with fibrillar lysozyme was followed by the enhancement of the monomer band and the reduction of the H-band. The absorption spectra measured at various fibril concentrations were analyzed in terms of the model allowing for the shift of equilibria between various dye species due to the binding of monomers and dimers of AK7-5 and AK7-6 to amyloid fibrils. The association constants and stoichiometries of the dye-fibril complexation have been evaluated. In contrast to fibrillar lysozyme, the native protein brought about strong J-aggregate formation accompanied by a marked drop in the absorbance of the dye monomer species. Quantum chemical calculations and simple docking studies showed that AK7-5 and AK7-6 monomers can bind to the grooves, running parallel to the fibril axis. Due to their ability to distinguish between the native and fibrillar protein states, the novel cyanines are recommended as complementary to existing amyloid markers.


Subject(s)
Carbocyanines/chemical synthesis , Fluorescent Dyes/chemical synthesis , Muramidase/chemistry , Binding Sites , Carbocyanines/chemistry , Fluorescent Dyes/chemistry , Models, Molecular , Molecular Docking Simulation , Protein Aggregates , Quantum Theory , Spectrometry, Fluorescence
10.
J Fluoresc ; 27(4): 1359-1363, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28283899

ABSTRACT

The present study was undertaken to design the novel liposomal drug formulation containing doxorubicin and europium coordination complexes. It was shown that co-encapsulation of the drugs facilitates the partitioning and permeation of lanthanides into the lipid bilayer. The obtained results suggest that new drug platform may have potential application in the design of novel antitumor agents.


Subject(s)
Coordination Complexes/chemistry , Doxorubicin/chemistry , Drug Carriers/chemistry , Europium/chemistry , Lanthanoid Series Elements/chemistry , Lipid Bilayers/chemistry , Liposomes/chemistry , Cell Membrane , Fluorescence , Humans , Permeability
11.
J Fluoresc ; 26(1): 177-87, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26521968

ABSTRACT

A series of symmetric pentamethine cyanine dyes derived from various N-substituted benzothiazolium/benzoselenazolium salts, and a conjugated bis-aniline derivative containing a chlorine atom at meso-position with respect to the polymethine chain, were synthesized using a novel improved synthetic approach under mild conditions at room temperature. The reaction procedure was held by grinding the starting compounds for relative short times. The novel method is reliable and highly reproducible. Some photophysical characteristics were recorded in various solvents, including absorption, and fluorescence quantum yields using Cy-5 as a reference. Additional studies on interactions with several bio-objects such as liposomes, DNA, and proteins have been investigated in the present work.


Subject(s)
Benzothiazoles/chemistry , Carbocyanines/chemistry , DNA/chemistry , Fluorescent Dyes/chemistry , Fluorescent Dyes/chemical synthesis , Liposomes/chemistry , Organoselenium Compounds/chemistry , Proteins/chemistry , Fluorescence , Molecular Structure , Photochemical Processes , Temperature
12.
Methods Appl Fluoresc ; 4(3): 034007, 2016 09 02.
Article in English | MEDLINE | ID: mdl-28355153

ABSTRACT

The applicability of a series of novel benzanthrone dyes to monitoring the changes in physicochemical properties of lipid bilayer and to differentiating between the native and aggregated protein states has been evaluated. Based on the quantitative parameters of the dye-membrane and dye-protein binding derived from the fluorimetric titration data, the most prospective membrane probes and amyloid tracers have been selected from the group of examined compounds. Analysis of the red edge excitation shifts of the membrane- and amyloid-bound dyes provided information on the properties of benzanthrone binding sites within the lipid and protein matrixes. To understand how amyloid specificity of benzanthrones correlates with their structure, quantitative structure activity relationship (QSAR) analysis was performed involving a range of quantum chemical molecular descriptors. A statistically significant model was obtained for predicting the sensitivity of novel benzanthrone dyes to amyloid fibrils.


Subject(s)
Benz(a)Anthracenes/chemistry , Amyloid , Binding Sites , Fluorescent Dyes , Lipid Bilayers , Molecular Probes , Prospective Studies , Protein Binding , Quantitative Structure-Activity Relationship , Spectrometry, Fluorescence
13.
Methods Appl Fluoresc ; 4(3): 034010, 2016 09 06.
Article in English | MEDLINE | ID: mdl-28355156

ABSTRACT

Fluorescence represents one of the most powerful tools for the detection and structural characterization of the pathogenic protein aggregates, amyloid fibrils. The traditional approaches to the identification and quantification of amyloid fibrils are based on monitoring the fluorescence changes of the benzothiazole dye thioflavin T (ThT) and absorbance changes of the azo dye Congo red (CR). In routine screening it is usually sufficient to perform only the ThT and CR assays, but both of them, when used separately, could give false results. Moreover, fibrillization kinetics can be measured only by ThT fluorescence, while the characteristic absorption spectra and birefringence of CR represent more rigid criteria for the presence of amyloid fibrils. Therefore, it seemed reasonable to use both these dyes simultaneously, combining the advantages of each technique. To this end, we undertook a detailed analysis of the fluorescence spectral behavior of these unique amyloid tracers upon their binding to amyloid fibrils from lysozyme, insulin and an N-terminal fragment of apolipoprotein A-I with Iowa mutation. The fluorescence measurements revealed several criteria for distinguishing between fibrillar and monomeric protein states: (i) a common drastic increase in ThT fluorescence intensity; (ii) a sharp decrease in ThT fluorescence upon addition of CR; (iii) an appearance of the maximum at 535-540 nm in the CR excitation spectra; (iv) increase in CR fluorescence intensity at 610 nm. Based on these findings we designed a novel combined ThT-CR fluorescence assay for amyloid identification. Such an approach not only strengthens the reliability of the ThT assay, but also provides new opportunities for structural characterization of amyloid fibrils.


Subject(s)
Congo Red/chemistry , Thiazoles/chemistry , Amyloid , Benzothiazoles , Fluorescence , Fluorescent Dyes , Kinetics , Protein Binding , Reproducibility of Results
14.
Methods Appl Fluoresc ; 4(3): 034014, 2016 09 21.
Article in English | MEDLINE | ID: mdl-28355160

ABSTRACT

Förster resonance energy transfer (FRET) is a powerful fluorescence technique that has found numerous applications in medicine and biology. One area where FRET proved to be especially informative involves the intermolecular interactions in biological membranes. The present study was focused on developing and verifying a Monte-Carlo approach to analyzing the results of FRET between the membrane-bound fluorophores. This approach was employed to quantify FRET from benzanthrone dye ABM to squaraine dye SQ-1 in the model protein-lipid system containing a polycationic globular protein lysozyme and negatively charged lipid vesicles composed of phosphatidylcholine and phosphatidylglycerol. It was found that acceptor redistribution between the lipid bilayer and protein binding sites resulted in the decrease of FRET efficiency. Quantification of this effect in terms of the proposed methodology yielded both structural and binding parameters of lysozyme-lipid complexes.


Subject(s)
Fluorescence Resonance Energy Transfer , Cell Membrane , Fluorescent Dyes , Lipid Bilayers , Phosphatidylcholines , Phosphatidylglycerols , Protein Binding
15.
Adv Exp Med Biol ; 855: 135-55, 2015.
Article in English | MEDLINE | ID: mdl-26149929

ABSTRACT

Amyloid fibrils are an intriguing class of protein aggregates with distinct physicochemical, structural and morphological properties. They display peculiar membrane-binding behavior, thus adding complexity to the problem of protein-lipid interactions. The consensus that emerged during the past decade is that amyloid cytotoxicity arises from a continuum of cross-ß-sheet assemblies including mature fibrils. Based on literature survey and our own data, in this chapter we address several aspects of fibril-lipid interactions, including (i) the effects of amyloid assemblies on molecular organization of lipid bilayer; (ii) competition between fibrillar and monomeric membrane-associating proteins for binding to the lipid surface; and (iii) the effects of lipids on the structural morphology of fibrillar aggregates. To illustrate some of the processes occurring in fibril-lipid systems, we present and analyze fluorescence data reporting on lipid bilayer interactions with fibrillar lysozyme and with the N-terminal 83-residue fragment of amyloidogenic mutant apolipoprotein A-I, 1-83/G26R/W@8. The results help understand possible mechanisms of interaction and mutual remodeling of amyloid fibers and lipid membranes, which may contribute to amyloid cytotoxicity.


Subject(s)
Amyloid/metabolism , Lipid Bilayers/metabolism , Animals , Binding, Competitive , Humans
16.
Soft Matter ; 11(31): 6223-34, 2015 Aug 21.
Article in English | MEDLINE | ID: mdl-26153461

ABSTRACT

Apolipoprotein A-I (apoA-I) is an amyloid-forming protein whose amyloidogenic properties are attributed mainly to its N-terminal fragment. Cell membranes are thought to be the primary target for the toxic amyloid aggregates. In the present study Förster resonance energy transfer (FRET) between the membrane fluorescent probe Laurdan as a donor and amyloid-specific dye Thioflavin T (ThT) as an acceptor was employed to explore the interactions of amyloid fibrils from apoA-I variants 1-83/G26R and 1-83/G26R/W@8 with the model membranes composed of phosphatidylcholine and its mixture with cholesterol. The changes in FRET efficiency upon fibril-lipid binding were found to correlate with the extent of protein fibrillization. AFM imaging revealed the presence of two polymorphic states of fibrillar 1-83/G26R/W@8 with the helical and twisted ribbon morphologies. The simulation-based analysis of the experimental FRET profiles provided the arguments in favor of untwisting of fibrillar assemblies upon their interaction with the model membranes. Evidence for the face-on orientation and superficial bilayer location of the membrane-bound fragments of 1-83/G26R/W@8 fibrils was obtained.


Subject(s)
Amyloid/chemistry , Apolipoprotein A-I/chemistry , Amyloid/metabolism , Apolipoprotein A-I/metabolism , Cell Membrane/chemistry , Cell Membrane/metabolism , Fluorescence Resonance Energy Transfer , Humans , Membranes, Artificial
17.
J Fluoresc ; 25(2): 253-61, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25595057

ABSTRACT

The binding of monomeric and aggregated variants of 1-83 N-terminal fragment of apolipoprotein A-I with substitution mutations G26R, G26R/W@8, G26R/W@50 and G26R/W@72 to the model lipid membranes composed of phosphatidylcholine and its mixture with cholesterol has been investigated using fluorescent probes pyrene and Laurdan. Examination of pyrene spectral behavior did not reveal any marked influence of apoA-I mutants on the hydrocarbon region of lipid bilayer. In contrast, probing the membrane effects by Laurdan revealed decrease in the probe generalized polarization in the presence of aggregated proteins. suggesting that oligomeric and fibrillar apoA-I species induce increase in hydration degree and reduction of lipid packing density in the membrane interfacial region. These findings may shed light on molecular details of amyloid cytotoxicity.


Subject(s)
Apolipoprotein A-I/chemistry , Cell Membrane/chemistry , Cell Membrane/metabolism , Fluorescent Dyes/chemistry , Peptide Fragments/chemistry , Peptide Fragments/metabolism , 2-Naphthylamine/analogs & derivatives , 2-Naphthylamine/chemistry , Amino Acid Sequence , Amyloid/chemistry , Cholesterol/chemistry , Humans , Laurates/chemistry , Lipid Bilayers/chemistry , Lipid Bilayers/metabolism , Molecular Sequence Data , Mutation , Peptide Fragments/genetics , Phosphatidylcholines/chemistry , Protein Multimerization , Pyrenes/chemistry
18.
J Fluoresc ; 24(3): 899-907, 2014 May.
Article in English | MEDLINE | ID: mdl-24596055

ABSTRACT

Förster resonance energy transfer (FRET) between anthrylvinyl-labeled phosphatidylcholine (AV-PC) as a donor and newly synthesized benzanthrones (referred to here as A8, A6, AM12, AM15 and AM18) as acceptors has been examined to gain insight into molecular level details of the interactions between benzanthrone dyes and model lipid membranes composed of zwitterionic lipid phosphatidylcholine and its mixtures with anionic lipids cardiolipin (CL) and phosphatidylglycerol (PG). FRET data were quantitatively analyzed in terms of the model of energy transfer in two-dimensional systems taking into account the distance dependence of orientation factor. Evidence for A8 location in phospholipid headgroup region has been obtained. Inclusion of CL and PG into PC bilayer has been found to induce substantial relocation of A6, AM12, AM15 and AM18 from hydrophobic membrane core to lipid-water interface.


Subject(s)
Benz(a)Anthracenes/chemistry , Cardiolipins/chemistry , Fluorescence Resonance Energy Transfer , Fluorescent Dyes/chemistry , Lipid Bilayers/chemistry , Phosphatidylglycerols/chemistry , Models, Theoretical , Phosphatidylcholines/chemistry , Spectrometry, Fluorescence
19.
J Struct Biol ; 185(1): 116-24, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24239554

ABSTRACT

Apolipoprotein A-I is amenable to a number of specific mutations associated with hereditary systemic amyloidoses. Amyloidogenic properties of apoA-I are determined mainly by its N-terminal fragment. In the present study Förster resonance energy transfer between tryptophan as a donor and Thioflavin T as an acceptor was employed to obtain structural information on the amyloid fibrils formed by apoA-I variant 1-83/G26R/W@8. Analysis of the dye-fibril binding data provided evidence for the presence of two types of ThT binding sites with similar stoichiometries (bound dye to monomeric protein molar ratio ∼10), but different association constants (∼6 and 0.1µM(-1)) and ThT quantum yields in fibril-associated state (0.08 and 0.05, respectively). A ß-strand-loop-ß-strand structural model of 1-83/G26R/W@8 apoA-I fibrils has been proposed, with potential ThT binding sites located in the solvent-exposed grooves of the N-terminal ß-sheet layer. Reasoning from the expanded FRET analysis allowing for heterogeneity of ThT binding centers and fibril polymorphism, the most probable locations of high- and low-affinity ThT binding sites were attributed to the grooves T16_Y18 and D20_L22, respectively.


Subject(s)
Amyloid/chemistry , Apolipoprotein A-I/chemistry , Thiazoles/chemistry , Benzothiazoles , Binding Sites , Energy Transfer , Humans , Protein Binding , Protein Interaction Domains and Motifs
20.
J Fluoresc ; 24(2): 493-504, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24371000

ABSTRACT

A series of novel fluorescent benzanthrone dyes have been tested for their ability to identify and characterize fibrillar aggregates of lysozyme prepared by protein denaturation in concentrated ethanol solution (F(eth)) or acidic buffer (F(ac)). Quantitative parameters of the dye association with native and fibrillar protein have been derived from the results of fluorimetric titration. The binding characteristics proved to be different for F(eth)- and F(ac)-bound benzanthrones, highlighting the dye sensitivity to the distinctions in fibril morphology. By comparing the dye preference to fibrillar protein aggregates, AM2, A8 and A6 were selected as the most prospective amyloid tracers. Based on the analysis of red edge excitation shifts and fluorescence lifetimes of the amyloid-bound dyes it was assumed that surface grooves or dry "steric zipper" interface are potential fibril binding sites for the novel fluorophores.


Subject(s)
Amyloid/chemistry , Benz(a)Anthracenes/chemistry , Coloring Agents/chemistry , Muramidase/chemistry , Benzothiazoles , Microscopy, Electron, Transmission , Spectrometry, Fluorescence , Thiazoles/chemistry
SELECTION OF CITATIONS
SEARCH DETAIL
...