Glycation of α-synuclein hampers its binding to synaptic-like vesicles and its driving effect on their fusion.

Parkinson's disease (PD) is one of the most prevalent neurodegenerative disorders affecting the worldwide population. One of its hallmarks is the intraneuronal accumulation of insoluble Lewy bodies (LBs), which cause the death of dopaminergic neurons. α-Synuclein (αS) is the main component of these LBs and in them, it commonly contains non-enzymatic post-translational modifications, such as those resulting from its reaction with reactive carbonyl species arising as side products of the intraneuronal glycolysis (mainly methylglyoxal). Consequently, lysines of the αS found in LBs of diabetic individuals are usually carboxyethylated. A precise comprehension of the effect of Nε-(carboxyethyl)lysine (CEL) on the aggregation of αS and on its physiological function becomes crucial to fully understand the molecular mechanisms underlying the development of diabetes-induced PD. Consequently, we have here used a synthetic αS where all its Lys have been replaced by CEL moieties (αS-CEL), and we have studied how these modifications could impact on the neurotransmission mechanism. This study allows us to describe how the non-enzymatic glycosylation (glycation) affects the function of a protein like αS, involved in the pathogenesis of PD. CEL decreases the ability of αS to bind micelles, although the micelle-bound fraction of αS-CEL still displays an α-helical fold resembling that of the lipid-bound αS. However, CEL completely abolishes the affinity of αS towards synaptic-like vesicles and, consequently, it hampers its physiological function as a catalyst of the clustering and the fusion of the synaptic vesicles.

Conceptual DFT-Based Computational Peptidology, Pharmacokinetics Study and ADMET Report of the Veraguamides A-G Family of Marine Natural Drugs.

As a continuation of our research on the chemical reactivity, pharmacokinetics and ADMET properties of cyclopeptides of marine origin with potential therapeutic abilities, in this work our already presented integrated molecular modeling protocol has been used for the study of the chemical reactivity and bioactivity properties of the Veraguamides A-G family of marine natural drugs. This protocol results from the estimation of the conceptual density functional theory (CDFT) chemical reactivity descriptors together with several chemoinformatics tools commonly considered within the process of development of new therapeutic drugs. CP-CDFT is a branch of computational chemistry and molecular modeling dedicated to the study of peptides, and it is a protocol that allows the estimation with great accuracy of the CDFT-based reactivity descriptors and the associated physical and chemical properties, which can aid in determining the ability of the studied peptides to behave as potential useful drugs. Moreover, the superiority of the MN12SX density functional over other long-range corrected density functionals for the prediction of chemical and physical properties in the presence of water as the solvent is clearly demonstrated. The research was supplemented with an investigation of the bioactivity of the molecular systems and their ADMET (absorption, distribution, metabolism, excretion, and toxicity) parameters, as is customary in medicinal chemistry. Some instances of the CDFT-based chemical reactivity descriptors' capacity to predict the pKas of peptides as well as their potential as AGE inhibitors are also shown.

Formation Mechanism of Inter-Crosslink in DNA by Nitrogen Oxides Pollutants through A Diazonium Intermediate.

Outdoor air pollution is a mixture of multiple atmospheric pollutants, among which nitrogen oxide (NOx) stands out due to its association with several diseases. NOx reactivity can conduct to DNA damage as severe as interstrand crosslinks (ICL) formation, that in turn is able to block DNA replication and transcription. Experimental studies have suggested that the ICL formation due to NOx is realized through a diazonium intermediate (DI). In this work, we have modeled the DI structure, including a DNA double-strand composed of two base pairs GC/CG, being diazotized as one of the guanine nucleotides. The structural stability of DNA with DI lesion was essayed through 500 ns molecular dynamics simulations. It was found that the DNA structure of the oligonucleotide is stable when the DI is present since the loss of a Guanine-Cytosine hydrogen bond is replaced by the presence of two cation-π interactions. Additionally, we have studied the mechanism of formation of a crosslink between the two guanine nucleobases from the modeled DI by carrying out DFT calculations at the M06-L/DNP+ level of theory. Our results show that the mechanism is thermodynamically favored by a strong stabilization of the ICL product, and the process is kinetically viable since its limiting stage is accessible.

In Vitro Anticancer Screening, Molecular Docking and Antimicrobial Studies of Triazole-Based Nickel(II) Metal Complexes.

Herein we describe the synthesis of a series of nickel(II) complexes (C1-C3) with Schiff bases (HL1-HL3) derived from 4-amino-5-mercapto-3-methyl-1,2,4-triazole and ortho/meta/para-nitrobenzaldehyde having composition [Ni(L)2(H2O)2]. The obtained ligands and their complexes were characterized using physico-chemical techniques viz., elemental analysis, magnetic moment study, spectral (electronic, FT-IR, 1H-NMR) and thermal analysis. The elemental analysis and spectral analysis revealed that Schiff bases behave as monoanionic bidentate ligands towards the Ni(II) ion. Whereas, the magnetic moment study suggested the octahedral geometry of all the Ni(II) complexes. The thermal behavior of the complexes has been studied by thermogravimetric analysis and agrees well with the composition of complexes. Further, the biological activities such as antimicrobial and antifungal studies of the Schiff bases and Ni(II) complexes have been screened against bacterial species (Staphylococcus aureus and Pseudomonas aeruginosa) and fungal species (Aspergillus niger and Candida albicans) activity by MIC method, the results of which revealed that metal complexes exhibited significant antimicrobial activities than their respective ligands against the tested microbial species. Furthermore, the molecular docking technique was employed to investigate the active sites of the selected protein, which indeed helped us to screen the potential anticancer agents among the synthesized ligand and complexes. Further, these compounds have been screened for their in vitro anticancer activity using OVCAR-3 cell line. The results revealed that the complexes are more active than the ligands.

N-((1H-Pyrrol-2-yl)methylene)-6-methoxypyridin-3-amine and Its Co(II) and Cu(II) Complexes as Antimicrobial Agents: Chemical Preparation, In Vitro Antimicrobial Evaluation, In Silico Analysis and Computational and Theoretical Chemistry Investigations.

Researchers are interested in Schiff bases and their metal complexes because they offer a wide range of applications. The chemistry of Schiff bases of heterocompounds has got a lot of attention because of the metal's ability to coordinate with Schiff base ligands. In the current study, a new bidentate Schiff base ligand, N-((1H-pyrrol-2-yl)methylene)-6-methoxypyridin-3-amine (MPM) has been synthesized by condensing 6-methoxypyridine-3-amine with pyrrole-2-carbaldehyde. Further, MPM is used to prepare Cu(II) and Co(II) metal complexes. Analytical and spectroscopic techniques are used for the structural elucidation of the synthesized compounds. Both MPM and its metal complexes were screened against Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Klebsiella pneumoniae species for antimicrobial studies. Furthermore, these compounds were subjected to in silico studies against bacterial proteins to comprehend their best non-bonded interactions. The results confirmed that the Schiff base ligand show considerably higher binding affinity with good hydrogen bonding and hydrophobic interactions against various tested microbial species. These results were complemented with a report of the Conceptual DFT global reactivity descriptors of the studied compounds together with their biological scores and their ADMET computed parameters.

Exploration of Anti-HIV Phytocompounds against SARS-CoV-2 Main Protease: Structure-Based Screening, Molecular Simulation, ADME Analysis and Conceptual DFT Studies.

The ever-expanding pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has gained attention as COVID-19 and caused an emergency in public health to an unmatched level to date. However, the treatments used are the only options; currently, no effective and licensed medications are available to combat disease transmission, necessitating further research. In the present study, an in silico-based virtual screening of anti-HIV bioactive compounds from medicinal plants was carried out through molecular docking against the main protease (Mpro) (PDB: 6LU7) of SARS-CoV-2, which is a key enzyme responsible for virus replication. A total of 16 anti-HIV compounds were found to have a binding affinity greater than -8.9 kcal/mol out of 150 compounds screened. Pseudohypericin had a high affinity with the energy of -10.2 kcal/mol, demonstrating amino acid residual interactions with LEU141, GLU166, ARG188, and GLN192, followed by Hypericin (-10.1 kcal/mol). Moreover, the ADME (Absorption, Distribution, Metabolism and Excretion) analysis of Pseudohypericin and Hypericin recorded a low bioavailability (BA) score of 0.17 and violated Lipinski's rule of drug-likeness. The docking and molecular simulations indicated that the quinone compound, Pseudohypericin, could be tested in vitro and in vivo as potent molecules against COVID-19 disease prior to clinical trials.This was also supported by the theoretical and computational studies conducted. The global and local descriptors, which are the underpinnings of Conceptual Density FunctionalTheory (CDFT) have beenpredicted through successful model chemistry, hoping that they could be of help in the comprehension of the chemical reactivity properties of the molecular systems considered in this study.

Virtual Screening for Potential Phytobioactives as Therapeutic Leads to Inhibit NQO1 for Selective Anticancer Therapy.

NAD(P)H:quinone acceptor oxidoreductase-1 (NQO1) is a ubiquitous flavin adenine dinucleotide-dependent flavoprotein that promotes obligatory two-electron reductions of quinones, quinonimines, nitroaromatics, and azo dyes. NQO1 is a multifunctional antioxidant enzyme whose expression and deletion are linked to reduced and increased oxidative stress susceptibilities. NQO1 acts as both a tumor suppressor and tumor promoter; thus, the inhibition of NQO1 results in less tumor burden. In addition, the high expression of NQO1 is associated with a shorter survival time of cancer patients. Inhibiting NQO1 also enables certain anticancer agents to evade the detoxification process. In this study, a series of phytobioactives were screened based on their chemical classes such as coumarins, flavonoids, and triterpenoids for their action on NQO1. The in silico evaluations were conducted using PyRx virtual screening tools, where the flavone compound, Orientin showed a better binding affinity score of -8.18 when compared with standard inhibitor Dicumarol with favorable ADME properties. An MD simulation study found that the Orientin binding to NQO1 away from the substrate-binding site induces a potential conformational change in the substrate-binding site, thereby inhibiting substrate accessibility towards the FAD-binding domain. Furthermore, with this computational approach we are offering a scope for validation of the new therapeutic components for their in vitro and in vivo efficacy against NQO1.

Investigation of Antifungal Properties of Synthetic Dimethyl-4-Bromo-1-(Substituted Benzoyl) Pyrrolo[1,2-a] Quinoline-2,3-Dicarboxylates Analogues: Molecular Docking Studies and Conceptual DFT-Based Chemical Reactivity Descriptors and Pharmacokinetics Evaluation.

Candida albicans, an opportunistic fungal pathogen, frequently colonizes immune-compromised patients and causes mild to severe systemic reactions. Only few antifungal drugs are currently in use for therapeutic treatment. However, evolution of a drug-resistant C. albicans fungal pathogen is of major concern in the treatment of patients, hence the clinical need for novel drug design and development. In this study, in vitro screening of novel putative pyrrolo[1,2-a]quinoline derivatives as the lead drug targets and in silico prediction of the binding potential of these lead molecules against C. albicans pathogenic proteins, such as secreted aspartic protease 3 (SAP3; 2H6T), surface protein ß-glucanase (3N9K) and sterol 14-alpha demethylase (5TZ1), were carried out by molecular docking analyses. Further, biological activity-based QSAR and theoretical pharmacokinetic analysis were analyzed. Here, in vitro screening of novel analogue derivatives as drug targets against C. albicans showed inhibitory potential in the concentration of 0.4 µg for BQ-06, 07 and 08, 0.8 µg for BQ-01, 03, and 05, 1.6 µg for BQ-04 and 12.5 µg for BQ-02 in comparison to the standard antifungal drug fluconazole in the concentration of 30 µg. Further, in silico analysis of BQ-01, 03, 05 and 07 analogues docked on chimeric 2H6T, 3N9K and 5TZ1 revealed that these analogues show potential binding affinity, which is different from the therapeutic antifungal drug fluconazole. In addition, these molecules possess good drug-like properties based on the determination of conceptual Density Functional Theory (DFT)-based descriptors, QSAR and pharmacokinetics. Thus, the study offers significant insight into employing pyrrolo[1,2-a]quinoline analogues as novel antifungal agents against C. albicans that warrants further investigation.

Unraveling the NaCl Concentration Effect on the First Stages of α-Synuclein Aggregation.

Intraneuronal aggregation of the intrinsically disordered protein α-synuclein is at the core of Parkinson's disease and related neurodegenerative disorders. Several reports show that the concentration of salts in the medium heavily affects its aggregation rate and fibril morphology, but a characterization of the individual monomeric conformations underlying these effects is still lacking. In this work, we have applied our α-synuclein-optimized coarse-grained molecular dynamics approach to decipher the structural features of the protein monomer under a range of NaCl concentrations (0.0-1.0 M). The results show that key intramolecular contacts between the terminal domains are lost at intermediate concentrations (leading to extended conformations likely to fibrillate), but recovered at high concentrations (leading to compact conformations likely to evolve toward amorphous aggregates). The pattern of direct interactions of the terminal α-synuclein domains with Na+ and Cl- ions plays a key role in explaining this effect. Our results are consistent with a recent study reporting a fibrillation enhancement at moderate NaCl concentrations but an inhibition at higher concentrations. The present work will contribute to improving our understanding of the structural features of monomeric α-synuclein, determining its NaCl-induced fibrillation propensity and the molecular basis of synucleinopathies, necessary for the future development of disease-halting therapies.

Virtual Screening of Marine Natural Compounds by Means of Chemoinformatics and CDFT-Based Computational Peptidology.

This work presents the results of a computational study of the chemical reactivity and bioactivity properties of the members of the theopapuamides A-D family of marine peptides by making use of our proposed methodology named Computational Peptidology (CP) that has been successfully considered in previous studies of this kind of molecular system. CP allows for the determination of the global and local descriptors that come from Conceptual Density Functional Theory (CDFT) that can give an idea about the chemical reactivity properties of the marine natural products under study, which are expected to be related to their bioactivity. At the same time, the validity of the procedure based on the adoption of the KID (Koopmans In DFT) technique, as well as the MN12SX/Def2TZVP/H2O model chemistry is successfully verified. Together with several chemoinformatic tools that can be used to improve the process of virtual screening, some additional properties of these marine peptides are identified related to their ability to behave as useful drugs. With the further objective of analyzing their bioactivity, some useful parameters for future QSAR studies, their predicted biological targets, and the ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) parameters related to the theopapuamides A-D pharmacokinetics are also reported.

Conceptual DFT-Based Computational Peptidology of Marine Natural Compounds: Discodermins A-H.

A methodology based on the concepts that arise from Density Functional Theory named Conceptual Density Functional Theory (CDFT) was chosen for the calculation of some global and local reactivity descriptors of the Discodermins A-H family of marine peptides through the consideration of the KID (Koopmans in DFT) technique that was successfully used in previous studies of this kind of molecular systems. The determination of active sites of the studied molecules for different kinds of reactivities was achieved by resorting to some CDFT-based descriptors like the Fukui functions as well as the Parr functions derived from Molecular Electron Density Theory (MEDT). A few properties identified with their ability to behave as a drug and the bioactivity of the peptides considered in this examination were acquired by depending on a homology model by studying the correlation with the known bioactivity of related molecules in their interaction with various biological receptors. With the further object of analyzing their bioactivity, some parameters of usefulness for future QSAR studies, their predicted biological targets, and the ADME (Absorption, Distribution, Metabolism, and Excretion) parameters related to the Discodermins A-H pharmacokinetics are also reported.

Preparation, Spectroscopic Characterization, Theoretical Investigations, and In Vitro Anticancer Activity of Cd(II), Ni(II), Zn(II), and Cu(II) Complexes of 4(3H)-Quinazolinone-Derived Schiff Base.

Herein, we report the synthesis and characterization of a new Schiff base ligand 3-[[(E)-(3-hydroxyphenyl)-methylidene]amino]-2-methyl-quinazolin-4(3H)-one (HAMQ) and its Cd(II), Ni(II), Zn(II), and Cu(II) complexes (C1-C4). The ligand HAMQ was synthesized by reacting 3-hydroxybenzaldehyde and 3-amino-2-methyl-4(3H)-quinazolinone in a 1:1 molar ratio. The structure of the ligand and its complexes (C1-C4) were evaluated using ultraviolet (UV)-visible (Vis) light spectroscopy, 1H-NMR, Fourier-transform infrared (FT-IR) spectroscopy, MS, elemental analysis, conductance data, and thermogravimetric analysis (TGA). The characterization results suggested that the bidentate ligand, HAMQ, coordinated to the metal center through the lactum oxygen and the azomethine nitrogen. Moreover, all the metal complexes were analyzed using powder X-ray diffraction studies, which revealed that all of them belong to a triclinic crystal system. The research was supplemented by density functional theory (DFT) studies on the IR and UV-Vis spectra, as well as the chemical reactivity of the HAMQ and its four metallic derivatives making use of conceptual density functional theory (CDFT) by means of KID (Koopmans in DFT) methodology. The synthesized complexes displayed significant in vitro anticancer activity against human cancer cell lines (HeLa and HCT-115).

A Coarse-Grained Molecular Dynamics Approach to the Study of the Intrinsically Disordered Protein α-Synuclein.

Intrinsically disordered proteins (IDPs) are not well described by a single 3D conformation but by an ensemble of them, which makes their structural characterization especially challenging, both experimentally and computationally. Most all-atom force fields are designed for folded proteins and give too compact IDP conformations. α-Synuclein is a well-known IDP because of its relation to Parkinson's disease (PD). To understand its role in this disease at the molecular level, an efficient methodology is needed for the generation of conformational ensembles that are consistent with its known properties (in particular, with its dimensions) and that is readily extensible to post-translationally modified forms of the protein, commonly found in PD patients. Herein, we have contributed to this goal by performing explicit-solvent, microsecond-long Replica Exchange with Solute Scaling (REST2) simulations of α-synuclein with the coarse-grained force field SIRAH, finding that a 30% increase in the default strength of protein-water interactions yields a much better reproduction of its radius of gyration. Other known properties of α-synuclein, such as chemical shifts, secondary structure content, and long-range contacts, are also reproduced. Furthermore, we have simulated a glycated form of α-synuclein to suggest the extensibility of the method to its post-translationally modified forms. The computationally efficient REST2 methodology in combination with coarse-grained representations will facilitate the simulations of this relevant IDP and its modified forms, enabling a better understanding of their roles in disease and potentially leading to efficient therapies.

Chemical Reactivity Theory and Empirical Bioactivity Scores as Computational Peptidology Alternative Tools for the Study of Two Anticancer Peptides of Marine Origin.

This work presents an account of the reactivity behavior of the anticancer marine drugs, Soblidotin and Tasidotin, based on the calculation of the global and local descriptors resulting from Chemical Reactivity Theory (CRT), also known as Conceptual DFT, for their consideration as a useful complement to approximations based on Molecular Docking. The information on the global and local reactivity descriptors of the Soblidotin and Tasidotin molecules, obtained through our proposed methodology, may be used for the design of new pharmaceutical analogs by relying on the chemical interactions between these peptides and their protein-type biological receptors. It can be concluded that the CRT approximation to the global and local chemical reactivity, based on the descriptors, can provide interesting information for the consideration of both molecules as potential therapeutic drugs. This is complemented by a study on Advanced Glycation Endproduct (AGE) inhibition, by comparison with the usual molecular systems considered for the task, as a re-purposing study. Finally, the bioactivity scores for Soblidotin and Tasidotin are predicted through an empirical procedure, based on comparison with molecular structures with well-known pharmacological properties.

CDFT-Based Reactivity Descriptors as a Useful MEDT Chemoinformatics Tool for the Study of the Virotoxin Family of Fungal Peptides.

Virotoxins are monocyclic peptides formed by at least five different compounds: alaviroidin, viroisin, deoxoviroisin, viroidin and deoxovirodin. These are toxic peptides singularly found in Amanita virosa mushrooms. Here we perform computational studies on the structural and electronic conformations of these peptides using the MN12SX/Def2TZVP/H2O chemistry model to investigate their chemical reactivity. CDFT-based descriptors (for Conceptual Density Functional Theory) (e.g., Parr functions and Nucleophilicity) are also considered. At the same time, other properties (e.g., pKas) will be determined and used to study virotoxins solubility and to inform decisions about repurposing these agents in medicinal chemistry.

Calculation of the Global and Local Conceptual DFT Indices for the Prediction of the Chemical Reactivity Properties of Papuamides A-F Marine Drugs.

A well-behaved model chemistry previously validated for the study of the chemical reactivity of peptides was considered for the calculation of the molecular properties and structures of the Papuamide family of marine peptides. A methodology based on Conceptual Density Functional Theory (CDFT) was chosen for the determination of the reactivity descriptors. The molecular active sites were associated with the active regions of the molecules related to the nucleophilic and electrophilic Parr functions. Finally, the drug-likenesses and the bioactivity scores for the Papuamide peptides were predicted through a homology methodology relating them with the calculated reactivity descriptors, while other properties such as the pKas were determined following a methodology developed by our group.

A Systematic DFT Study of Some Plausible Zn(II) and Al(III) Interaction Sites in N-Terminally Acetylated α-Synuclein.

The interactions between the protein α-synuclein and the Zn(II) and Al(III) cations at different sites were studied at the M06/6-311+G(d,p)/SMD and the ωB97X-D/6-311+G(d,p)/SMD levels of theory. For Zn(II), previous experimental studies determined the presence of a high affinity site at Asp121 and a lower affinity one at His50. As for Al(III), an in vitro study showed it to be the most effective cation to induce structural changes in α-synuclein and to accelerate its aggregation. Besides Zn(II) and Al(III), Cu(II) also binds α-synuclein (in fact, its complexes are the most studied and the best characterized ones) forming square planar complexes, and several binding sites are known for it, involving Met1-Asp2 (only in nonacetylated α-synuclein), His50, and Asp121. Herein, we applied a simple theoretical methodology, which satisfactorily reproduces experimental geometries and energies for complexes of N-terminally acetylated α-synuclein with Cu(II), to study Zn(II) and Al(III) complexes at those same sites, as well as at some structurally analogous alternative sites. We found binding geometries for Zn(II) and Al(III) that differ from the ones for Cu(II). These results can help to understand the interactions between α-synuclein and metals, one of the factors leading to the formation of potentially neurotoxic α-synuclein aggregates.

Chemical Reactivity Properties, pKa Values, AGEs Inhibitor Abilities and Bioactivity Scores of the Mirabamides A⁻H Peptides of Marine Origin Studied by Means of Conceptual DFT.

The MN12SX density functional, in connection with the Def2TZVP basis set, was assessed, together with the SMD solvation model (Solvation Model based on the Density), for calculation of the molecular properties and structure of a group of peptides of marine origin named Mirabamides A⁻H. All the chemical reactivity descriptors for the systems were calculated via Conceptual Density Functional Theory (CDFT). The active sites suitable for nucleophilic, electrophilic, and radical attacks were chosen by linking them with the Fukui function indices, nucleophilic and electrophilic Parr functions, and condensed Dual Descriptor Δ f ( r ) , respectively. Additionally, the p K a values for the different peptides are predicted with great accuracy as well as the ability of the studied molecule in acting as an efficient inhibitor of the formation of Advanced Glycation Endproducts (AGEs), which constitutes a useful knowledge for the development of drugs for fighting Diabetes, Alzheimer and Parkinson diseases. Finally, the bioactivity scores for the Mirabamides A⁻H are predicted through different methodologies.

Molecular Reactivity and Absorption Properties of Melanoidin Blue-G1 through Conceptual DFT.

This computational study presents the assessment of eleven density functionals that include CAM-B3LYP, LC-wPBE, M11, M11L, MN12L, MN12SX, N12, N12SX, wB97, wB97X and wB97XD related to the Def2TZVP basis sets together with the Solvation Model Density (SMD) solvation model in calculating the molecular properties and structure of the Blue-G1 intermediate melanoidin pigment. The chemical reactivity descriptors for the system are calculated via the conceptual Density Functional Theory (DFT). The choice of the active sites related to the nucleophilic, electrophilic, as well as radical attacks is made by linking them with the Fukui function indices, the electrophilic Parr functions and the condensed dual descriptor Δ f ( r ) . The prediction of the maximum absorption wavelength tends to be considerably accurate relative to its experimental value. The study found the MN12SX and N12SX density functionals to be the most appropriate density functionals in predicting the chemical reactivity of the studied molecule.

Copper(II) Binding Sites in N-Terminally Acetylated α-Synuclein: A Theoretical Rationalization.

The interactions between N-terminally acetylated α-synuclein and Cu(II) at several binding sites have been studied with DFT calculations, specifically with the M06 hybrid functional and the ωB97X-D DFT-D functional. In previous experimental studies, Cu(II) was shown to bind several α-synuclein residues, including Met1-Asp2 and His50, forming square planar coordination complexes. Also, it was determined that a low-affinity binding site exists in the C-terminal domain, centered on Asp121. However, in the N-terminally acetylated protein, present in vivo, the Met1 site is blocked. In this work, we simplify the representation of the protein by modeling each experimentally found binding site as a complex between an N-terminally acetylated α-synuclein dipeptide (or several independent residues) and a Cu(II) cation, and compare the results with a number of additional, structurally analogous sites not experimentally found. This way of representing the binding sites, although extremely simple, allows us to reproduce experimental results and to provide a theoretical rationale to explain the preference of Cu(II) for certain sites, as well as explicit geometrical structures for the complexes formed. These results are important to understand the interactions between α-synuclein and Cu(II), one of the factors inducing structural changes in the protein and leading to aggregated forms of it which may play a role in neurodegeneration.