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1.
Phys Chem Chem Phys ; 24(4): 2126-2138, 2022 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-35029245

RESUMEN

Recent experimental findings pointed out a new mutation in the HCV protease, Q41R, responsible for a significant enhancement of the enzyme's reactivity towards the mitochondrial antiviral-signaling protein (MAVS). The Q41R mutation is located rather far from the active site, and its involvement in the overall reaction mechanism is thus unclear. We used classical molecular dynamics and QM/MM to study the acylation reaction of HCV NS3/4A protease variants bound to MAVS and the NS4A/4B substrate and uncovered the indirect mechanism by which the Q41R mutation plays a critical role in the efficient cleavage of the substrate. Our simulations reveal that there are two major conformations of the MAVS H1'(p) residue for the wild type protease and only one conformation for the Q41R mutant. The conformational space of H1'(p) is restricted by the Q41R mutation due to a π-π stacking between H1'(p) and R41 as well as a strong hydrogen bond between the backbone of H57 and the side chain of R41. Further QM/MM calculations indicate that the complex with the conformation ruled out by the Q41R substitution is a non-reactive species due to its higher free energy barrier for the acylation reaction. Based on our calculations, we propose a kinetic mechanism that explains experimental data showing an increase of apparent rate constants for MAVS cleavage in Q41R mutants. Our model predicts that the non-reactive conformation of the enzyme-substrate complex modulates reaction kinetics like an uncompetitive inhibitor.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/química , Serina Proteasas/química , Proteínas no Estructurales Virales/química , Acilación , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Dominio Catalítico , Hepacivirus/enzimología , Cinética , Simulación de Dinámica Molecular , Mutación , Unión Proteica , Conformación Proteica , Teoría Cuántica , Serina Proteasas/genética , Serina Proteasas/metabolismo , Termodinámica , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo
2.
Beilstein J Org Chem ; 18: 1-12, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35047078

RESUMEN

The development of peptide stapling techniques to stabilise α-helical secondary structure motifs of peptides led to the design of modulators of protein-protein interactions, which had been considered undruggable for a long time. We disclose a novel approach towards peptide stapling utilising macrocyclisation by late-stage Suzuki-Miyaura cross-coupling of bromotryptophan-containing peptides of the catenin-binding domain of axin. Optimisation of the linker length in order to find a compromise between both sufficient linker rigidity and flexibility resulted in a peptide with an increased α-helicity and enhanced binding affinity to its native binding partner ß-catenin. An increased proteolytic stability against proteinase K has been demonstrated.

3.
J Biol Chem ; 295(40): 13862-13874, 2020 10 02.
Artículo en Inglés | MEDLINE | ID: mdl-32747444

RESUMEN

Inhibitors against the NS3-4A protease of hepatitis C virus (HCV) have proven to be useful drugs in the treatment of HCV infection. Although variants have been identified with mutations that confer resistance to these inhibitors, the mutations do not restore replicative fitness and no secondary mutations that rescue fitness have been found. To gain insight into the molecular mechanisms underlying the lack of fitness compensation, we screened known resistance mutations in infectious HCV cell culture with different genomic backgrounds. We observed that the Q41R mutation of NS3-4A efficiently rescues the replicative fitness in cell culture for virus variants containing mutations at NS3-Asp168 To understand how the Q41R mutation rescues activity, we performed protease activity assays complemented by molecular dynamics simulations, which showed that protease-peptide interactions far outside the targeted peptide cleavage sites mediate substrate recognition by NS3-4A and support protease cleavage kinetics. These interactions shed new light on the mechanisms by which NS3-4A cleaves its substrates, viral polyproteins and a prime cellular antiviral adaptor protein, the mitochondrial antiviral signaling protein MAVS. Peptide binding is mediated by an extended hydrogen-bond network in NS3-4A that was effectively optimized for protease-MAVS binding in Asp168 variants with rescued replicative fitness from NS3-Q41R. In the protease harboring NS3-Q41R, the N-terminal cleavage products of MAVS retained high affinity to the active site, rendering the protease susceptible for potential product inhibition. Our findings reveal delicately balanced protease-peptide interactions in viral replication and immune escape that likely restrict the protease adaptive capability and narrow the virus evolutionary space.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales , Hepacivirus/fisiología , Simulación de Dinámica Molecular , Inhibidores de Proteasas/farmacología , Replicación Viral/efectos de los fármacos , Proteínas Adaptadoras Transductoras de Señales/química , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Sustitución de Aminoácidos , Línea Celular Tumoral , Humanos , Mutación Missense , Serina Proteasas/química , Serina Proteasas/genética , Serina Proteasas/metabolismo , Proteínas no Estructurales Virales/antagonistas & inhibidores , Proteínas no Estructurales Virales/química , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo , Replicación Viral/genética
4.
J Chem Inf Model ; 59(1): 206-214, 2019 01 28.
Artículo en Inglés | MEDLINE | ID: mdl-30433776

RESUMEN

Semi-empirical quantum methods from the neglect of differential diatomic overlap (NDDO) family such as MNDO, AM1, or PM3 are fast albeit approximate quantum methods. By combining them with linear scaling methods like the divide & conquer (D&C) method, it is possible to quickly evaluate the energy of systems containing hundreds to thousands of atoms. We here present our implementation in the Amber biomolecular package of a SEBOMD module that provides a way to run semi-empirical Born-Oppenheimer molecular dynamics. At each step of a SEBOMD, a fully converged self-consistent field (SCF) calculation is performed to obtain the semiempirical quantum potential energy of a molecular system encaged or not in periodic boundary conditions. We describe the implementation and the features of our SEBOMD implementation. We show the requirements to conserve the total energy in NVE simulations, and how to accelerate SCF convergence through density matrix extrapolation. Specific ways of handling periodic boundary conditions using mechanical embedding or electrostatic embedding through a tailored quantum Ewald summation is developed. The parallel performance of SEBOMD simulations using the D&C scheme are presented for liquid water systems of various sizes, and a comparison between the traditional full diagonalization scheme and the D&C approach for the reproduction of the structure of liquid water illustrates the potentiality of SEBOMD to simulate molecular systems containing several hundreds of atoms for hundreds of picoseconds with a quantum mechanical potential in a reasonable amount of CPU time.


Asunto(s)
Simulación de Dinámica Molecular , Teoría Cuántica , Electricidad Estática , Termodinámica , Agua/química
5.
Biochemistry ; 57(9): 1542-1551, 2018 03 06.
Artículo en Inglés | MEDLINE | ID: mdl-29412654

RESUMEN

Topotecan (TPT) is a nontoxic anticancer drug characterized by a pH-dependent lactone/carboxyl equilibrium. TPT acts on the covalently bonded DNA/topoisomerase I (DNA/TopoI) complex by intercalating between two DNA bases at the active site. This turns TopoI into a DNA-damaging agent and inhibits supercoil relaxation. Although only the lactone form of the drug is active and effectively inhibits TopoI, both forms have been co-crystallized at the same location within the DNA/TopoI complex. To gain further insights into the pH-dependent activity of TPT, the differences between two TPT:DNA/TopoI complexes presenting either the lactone (acidic pH) or the carboxyl (basic pH) form of TPT were studied by means of molecular dynamic simulations, quantum mechanical/molecular mechanical calculations, and topological analysis. We identified two specific amino acids that have a direct relationship with the activity of the drug, i.e., lysine 532 (K532) and asparagine 722 (N722). K532 forms a stable hydrogen bond bridge between TPT and DNA only when the drug is in its active lactone form. The presence of the active drug triggers the formation of an additional stable interaction between DNA and protein residues, where N722 acts as a bridge between the two fragments, thus increasing the binding affinity of DNA for TopoI and further slowing the release of DNA. Overall, our results provide a clear understanding of the activity of the TPT-like class of molecules and can help in the future design of new anticancer drugs targeting topoisomerase enzymes.


Asunto(s)
ADN-Topoisomerasas de Tipo I/química , ADN-Topoisomerasas de Tipo I/metabolismo , Topotecan/química , Topotecan/farmacología , Asparagina/química , Asparagina/metabolismo , ADN/química , ADN/metabolismo , Humanos , Lisina/química , Lisina/metabolismo , Simulación de Dinámica Molecular , Teoría Cuántica , Relación Estructura-Actividad , Termodinámica , Inhibidores de Topoisomerasa I/química , Inhibidores de Topoisomerasa I/farmacología
6.
Biochim Biophys Acta Bioenerg ; 1859(5): 342-356, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29499187

RESUMEN

In Photosystem II (PSII), the Mn4CaO5-cluster of the active site advances through five sequential oxidation states (S0 to S4) before water is oxidized and O2 is generated. Here, we have studied the transition between the low spin (LS) and high spin (HS) configurations of S2 using EPR spectroscopy, quantum chemical calculations using Density Functional Theory (DFT), and time-resolved UV-visible absorption spectroscopy. The EPR experiments show that the equilibrium between S2LS and S2HS is pH dependent, with a pKa ≈ 8.3 (n ≈ 4) for the native Mn4CaO5 and pKa ≈ 7.5 (n ≈ 1) for Mn4SrO5. The DFT results suggest that exchanging Ca with Sr modifies the electronic structure of several titratable groups within the active site, including groups that are not direct ligands to Ca/Sr, e.g., W1/W2, Asp61, His332 and His337. This is consistent with the complex modification of the pKa upon the Ca/Sr exchange. EPR also showed that NH3 addition reversed the effect of high pH, NH3-S2LS being present at all pH values studied. Absorption spectroscopy indicates that NH3 is no longer bound in the S3TyrZ state, consistent with EPR data showing minor or no NH3-induced modification of S3 and S0. In both Ca-PSII and Sr-PSII, S2HS was capable of advancing to S3 at low temperature (198 K). This is an experimental demonstration that the S2LS is formed first and advances to S3via the S2HS state without detectable intermediates. We discuss the nature of the changes occurring in the S2LS to S2HS transition which allow the S2HS to S3 transition to occur below 200 K. This work also provides a protocol for generating S3 in concentrated samples without the need for saturating flashes.


Asunto(s)
Cianobacterias/enzimología , Complejo de Proteína del Fotosistema II/química , Agua/química , Oxidación-Reducción , Complejo de Proteína del Fotosistema II/metabolismo , Agua/metabolismo
7.
Chemistry ; 24(4): 953-961, 2018 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-29160605

RESUMEN

Peptidotriazolamers are hybrid foldamers combining features of peptides and triazolamers-repetitive peptidomimetic structures with triazoles replacing peptide bonds. We report on the synthesis of a new class of peptidomimetics, containing 1,5-disubstituted 1,2,3-triazoles in an alternating fashion with amide bonds and the analysis of their conformation in solid state and solution. Homo- or heterochiral peptidotriazolamers were obtained from enantiomerically pure propargylamines with stereogenic centers in the propargylic position and α-azido esters by ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) under microwave conditions in high yields. With such building blocks the peptidotriazolamers are readily available by solution phase synthesis. While the conformation of the homochiral peptidotriazolamer Boc-Ala[5Tz]Phe-Val[5Tz]Ala-Leu[5Tz]Val-OBzl resembles that of a ß VIa1 turn, the heterochiral peptidotriazolamer Boc-d-Ala[5Tz]Phe-d-Val[5Tz]Ala-d-Leu[5Tz]Val-OBzl adopts a polyproline-like repetitive structure.

8.
J Chem Inf Model ; 58(1): 90-110, 2018 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-29112399

RESUMEN

Peptidomimetics are molecules of particular interest in the context of drug design and development. They are proteolytically and metabolically more stable than their natural peptide counterparts but still offer high specificity toward their biological targets. In recent years, 1,4- and 1,5-disubstituted 1,2,3-triazole-based peptidomimetics have emerged as promising lead compounds for the design of various inhibitory and tumor-targeting molecules as well as for the synthesis of peptide analogues. The growing popularity of triazole-based peptidomimetics and a constantly broadening range of their application generated a demand for elaborate theoretical investigations by classical molecular dynamics simulations and molecular docking. Despite this rising interest, accurate and coherent force field parameters for triazole-based peptidomimetics are still lacking. Here, we report the first complete set of parameters dedicated to this group of compounds, named TZLff. This parametrization is compatible with the latest version of the AMBER force field (ff14SB) and can be readily applied for the modeling of pure triazole-based peptidomimetics as well as natural peptide sequences containing one or more triazole-based modifications in their backbone. The parameters were optimized to reproduce HF/6-31G* electrostatic potentials as well as MP2/cc-pVTZ equilibrium Hessian matrices and conformational potential energy surfaces through the use of a genetic algorithm-based search and least-squares fitting. Following the standards of AMBER, we introduce residue building units, thus allowing the user to define any given sequence of triazole-based peptidomimetics. Validation of the parameter set against ab initio- and NMR-based reference systems shows that we obtain fairly accurate results, which properly capture the conformational features of triazole-based peptidomimetics. The successful and efficient parametrization strategy developed in this work is general enough to be applied in a straightforward manner for parametrization of other peptidomimetics and, potentially, any polymeric assemblies.


Asunto(s)
Péptidos/química , Peptidomiméticos , Triazoles/química , Algoritmos , Química Clic , Espectroscopía de Resonancia Magnética , Simulación de Dinámica Molecular , Polímeros/química
9.
BMC Struct Biol ; 17(1): 2, 2017 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-28148269

RESUMEN

BACKGROUND: T cell receptor (TCR) molecules are involved in the adaptive immune response as they distinguish between self- and foreign-peptides, presented in major histocompatibility complex molecules (pMHC). Former studies showed that the association angles of the TCR variable domains (Vα/Vß) can differ significantly and change upon binding to the pMHC complex. These changes can be described as a rotation of the domains around a general Center of Rotation, characterized by the interaction of two highly conserved glutamine residues. METHODS: We developed a computational method, DynaDom, for the prediction of TCR Vα/Vß inter-domain and TCR/pMHC orientations in TCRpMHC complexes, which allows predicting the orientation of multiple protein-domains. In addition, we implemented a new approach to predict the correct orientation of the carboxamide endgroups in glutamine and asparagine residues, which can also be used as an external, independent tool. RESULTS: The approach was evaluated for the remodeling of 75 and 53 experimental structures of TCR and TCRpMHC (class I) complexes, respectively. We show that the DynaDom method predicts the correct orientation of the TCR Vα/Vß angles in 96 and 89% of the cases, for the poses with the best RMSD and best interaction energy, respectively. For the concurrent prediction of the TCR Vα/Vß and pMHC orientations, the respective rates reached 74 and 72%. Through an exhaustive analysis, we could show that the pMHC placement can be further improved by a straightforward, yet very time intensive extension of the current approach. CONCLUSIONS: The results obtained in the present remodeling study prove the suitability of our approach for interdomain-angle optimization. In addition, the high prediction rate obtained specifically for the energetically highest ranked poses further demonstrates that our method is a powerful candidate for blind prediction. Therefore it should be well suited as part of any accurate atomistic modeling pipeline for TCRpMHC complexes and potentially other large molecular assemblies.


Asunto(s)
Biología Computacional/métodos , Antígenos de Histocompatibilidad Clase I/química , Fragmentos de Péptidos/química , Receptores de Antígenos de Linfocitos T alfa-beta/química , Animales , Sitios de Unión , Antígenos de Histocompatibilidad Clase I/metabolismo , Humanos , Ratones , Modelos Moleculares , Fragmentos de Péptidos/metabolismo , Unión Proteica , Receptores de Antígenos de Linfocitos T alfa-beta/metabolismo
10.
Biochemistry ; 54(6): 1429-39, 2015 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-25602614

RESUMEN

Deamidation is the uncatalyzed process by which asparagine or glutamine can be transformed into aspartic acid or glutamic acid, respectively. In its active homodimeric form, mammalian triosephosphate isomerase (TPI) contains two deamidation sites per monomer. Experimental evidence shows that the primary deamidation site (Asn71-Gly72) deamidates faster than the secondary deamidation site (Asn15-Gly16). To evaluate the factors controlling the rates of these two deamidation sites in TPI, we have performed graphics processing unit-enabled microsecond long molecular dynamics simulations of rabbit TPI. The kinetics of asparagine dipeptide and two deamidation sites in mammalian TPI are also investigated using quantum mechanical/molecular mechanical tools with the umbrella sampling technique. Analysis of the simulations has been performed using independent global and local descriptors that can influence the deamidation rates: desolvation effects, backbone acidity, and side chain conformations. Our findings show that all the descriptors add up to favor the primary deamidation site over the secondary one in mammalian TPI: Asn71 deamidates faster because it is more solvent accessible, the adjacent glycine NH backbone acidity is enhanced, and the Asn side chain has a preferential near attack conformation. The crucial impact of the backbone amide acidity of the adjacent glycine on the deamidation rate is shown by kinetic analysis. Our findings also shed light on the effect of high-order structure on deamidation: the deamidation in a small peptide is favored first because of the higher reactivity of the asparagine residue and then because of the stronger stability of the tetrahedral intermediate.


Asunto(s)
Amidas/química , Asparagina/química , Teoría Cuántica , Triosa-Fosfato Isomerasa/química , Animales , Simulación de Dinámica Molecular
11.
J Chem Inf Model ; 54(8): 2200-13, 2014 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-25089727

RESUMEN

In a first step toward the development of an efficient and accurate protocol to estimate amino acids' pKa's in proteins, we present in this work how to reproduce the pKa's of alcohol and thiol based residues (namely tyrosine, serine, and cysteine) in aqueous solution from the knowledge of the experimental pKa's of phenols, alcohols, and thiols. Our protocol is based on the linear relationship between computed atomic charges of the anionic form of the molecules (being either phenolates, alkoxides, or thiolates) and their respective experimental pKa values. It is tested with different environment approaches (gas phase or continuum solvent-based approaches), with five distinct atomic charge models (Mulliken, Löwdin, NPA, Merz-Kollman, and CHelpG), and with nine different DFT functionals combined with 16 different basis sets. Moreover, the capability of semiempirical methods (AM1, RM1, PM3, and PM6) to also predict pKa's of thiols, phenols, and alcohols is analyzed. From our benchmarks, the best combination to reproduce experimental pKa's is to compute NPA atomic charge using the CPCM model at the B3LYP/3-21G and M062X/6-311G levels for alcohols (R(2) = 0.995) and thiols (R(2) = 0.986), respectively. The applicability of the suggested protocol is tested with tyrosine and cysteine amino acids, and precise pKa predictions are obtained. The stability of the amino acid pKa's with respect to geometrical changes is also tested by MM-MD and DFT-MD calculations. Considering its strong accuracy and its high computational efficiency, these pKa prediction calculations using atomic charges indicate a promising method for predicting amino acids' pKa in a protein environment.


Asunto(s)
Alcoholes/química , Cisteína/química , Fenoles/química , Serina/química , Compuestos de Sulfhidrilo/química , Tirosina/química , Modelos Químicos , Proteínas/química , Teoría Cuántica , Electricidad Estática , Termodinámica , Agua/química
12.
J Chem Phys ; 141(3): 034106, 2014 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-25053300

RESUMEN

In this work, we present a study of the ability of different semiempirical methods to describe intermolecular interactions in water solution. In particular, we focus on methods based on the Neglect of Diatomic Differential Overlap approximation. Significant improvements of these methods have been reported in the literature in the past years regarding the description of non-covalent interactions. In particular, a broad range of methodologies has been developed to deal with the properties of hydrogen-bonded systems, with varying degrees of success. In contrast, the interactions between water and a molecule containing hydrophobic groups have been little analyzed. Indeed, by considering the potential energy surfaces obtained using different semiempirical Hamiltonians for the intermolecular interactions of model systems, we found that none of the available methods provides an entirely satisfactory description of both hydrophobic and hydrophilic interactions in water. In addition, a vibrational analysis carried out in a model system for these interactions, a methane clathrate cluster, showed that some recent methods cannot be used to carry out studies of vibrational properties. Following a procedure established in our group [M. I. Bernal-Uruchurtu, M. T. C. Martins-Costa, C. Millot, and M. F. Ruiz-López, J. Comput. Chem. 21, 572 (2000); W. Harb, M. I. Bernal-Uruchurtu, and M. F. Ruiz-López, Theor. Chem. Acc. 112, 204 (2004)], we developed new parameters for the core-core interaction terms based on fitting potential energy curves obtained at the MP2 level for our model system. We investigated the transferability of the new parameters to describe a system, having both hydrophilic and hydrophobic groups, interacting with water. We found that only by introducing two different sets of parameters for hydrophilic and hydrophobic hydrogen atom types we are able to match the features of the ab initio calculated properties. Once this assumption is made, a good agreement with the MP2 reference is achieved. The results reported in this work provide therefore a direction for future developments of semiempirical approaches that are still required to investigate chemical processes in biomolecules and in large disordered systems.

13.
ACS Omega ; 8(22): 19656-19662, 2023 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-37305285

RESUMEN

Aggregation-induced emission (AIE) is a phenomenon where certain molecules or materials become highly luminescent when they aggregate or come together in a condensed state, such as a solid or a solution. Moreover, new molecules which show AIE properties are designed and synthesized for various applications like imaging, sensing, and optoelectronics. 2,3,5,6-Tetraphenylpyrazine (TPP) is one of the well-established examples of AIE. Herein, 2,3,5,6-tetraphenyl-1,4-dioxin (TPD) and 2,3,4,5-tetraphenyl-4H-pyran-4-one (TPPO), which are old molecules with TPP similarity, were studied, and new insights in terms of structure and aggregation-caused quenching (ACQ)/AIE properties were gained by means of theoretical calculations. Those calculations performed on TPD and TPPO aimed to provide a better understanding of their molecular structures and how they affect their luminescence properties. This information could be used to design new materials with improved AIE properties or to modify existing materials to overcome ACQ.

14.
ACS Appl Bio Mater ; 5(6): 2754-2767, 2022 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-35537187

RESUMEN

Activity-based theranostic photosensitizers are highly attractive in photodynamic therapy as they offer enhanced therapeutic outcome on cancer cells with an imaging opportunity at the same time. However, photosensitizers (PS) cores that can be easily converted to activity-based photosensitizers (aPSs) are still quite limited in the literature. In this study, we modified the dicyanomethylene-4H-chromene (DCM) core with a heavy iodine atom to get two different PSs (DCMO-I, I-DCMO-Cl) that can be further converted to aPS after simple modifications. The effect of iodine positioning on singlet oxygen generation capacity was also evaluated through computational studies. DCMO-I showed better performance in solution experiments and further proved to be a promising phototheranostic scaffold via cell culture studies. Later, a cysteine (Cys) activatable PS based on the DCMO-I core (DCMO-I-Cys) was developed, which induced selective photocytotoxicity along with a fluorescence turn-on response in Cys rich cancer cells.


Asunto(s)
Yodo , Neoplasias , Fotoquimioterapia , Fluorescencia , Yodo/uso terapéutico , Neoplasias/tratamiento farmacológico , Fotoquimioterapia/métodos , Fármacos Fotosensibilizantes/farmacología , Oxígeno Singlete/uso terapéutico
15.
ACS Appl Mater Interfaces ; 13(38): 45854-45863, 2021 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-34520162

RESUMEN

The design of catalysts with greater control over catalytic activity and stability is a major challenge with substantial impact on fundamental chemistry and industrial applications. Due to their unparalleled diversity, selectivity, and efficiency, enzymes are promising models for next-generation catalysts, and considerable efforts have been devoted to incorporating the principles of their mechanisms of action into artificial systems. We report a heretofore undocumented catalyst design that introduces fullerenes to the field of biocatalysis, which we refer to as fullerene nanocatalysts, and that emulates enzymatic active sites through multifunctional self-assembled nanostructures. As a proof-of-concept, we mimicked the reactivity of hydrolases using fullerene nanocatalysts functionalized with the basic components of the parent enzyme with remarkable activity. Owing to the versatile amino acid-based functionalization repertoire of fullerene nanocatalysts, these next-generation carbon/biomolecule hybrids have potential to mimic the activity of other families of enzymes and, therefore, offer new perspectives for the design of biocompatible, high-efficiency artificial nanocatalysts.


Asunto(s)
Materiales Biomiméticos/química , Fulerenos/química , Nanoestructuras/química , Aminoácidos/química , Aminoácidos/toxicidad , Materiales Biomiméticos/toxicidad , Catálisis , Fulerenos/toxicidad , Humanos , Cinética , Células MCF-7 , Simulación de Dinámica Molecular , Nanoestructuras/toxicidad , Oxidación-Reducción
16.
J Med Chem ; 64(1): 586-601, 2021 01 14.
Artículo en Inglés | MEDLINE | ID: mdl-33356253

RESUMEN

An array of l- and d-halotryptophans with different substituents at the indole moiety was synthesized employing either enzymatic halogenation by halogenases or incorporation of haloindoles using tryptophan synthase. Introduction of these Trp derivatives into RGD peptides as a benchmark system was performed to investigate their influence on bioactivity. Halotryptophan-containing RGD peptides display increased affinity toward integrin αvß3 and enhanced selectivity over integrin α5ß1. In addition, bromotryptophan was exploited as a platform for late-stage diversification by Suzuki-Miyaura cross-coupling (SMC), resulting in new-to-nature biaryl motifs. These peptides show enhanced affinity toward αvß3, good affinity to αvß8, and remarkable selectivity over α5ß1 and αIIbß3 while featuring fluorogenic properties. Their feasibility as a probe was demonstrated in vitro. Extensive molecular dynamics simulations were undertaken to elucidate NMR and high-performance liquid chromatography (HPLC) data for these late-stage diversified cyclic RGD peptides and to further characterize their conformational preferences.


Asunto(s)
Halógenos/química , Oligopéptidos/farmacología , Triptófano/química , Cromatografía Líquida de Alta Presión/métodos , Estudios de Factibilidad , Concentración 50 Inhibidora , Espectroscopía de Resonancia Magnética/métodos , Simulación de Dinámica Molecular , Oligopéptidos/química , Relación Estructura-Actividad
17.
Chempluschem ; 86(6): 840-851, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33905181

RESUMEN

In peptidotriazolamers every second peptide bond is replaced by a 1H-1,2,3-triazole. Such foldamers are expected to bridge the gap in molecular weight between small-molecule drugs and protein-based drugs. Amyloid ß (Aß) aggregates play an important role in Alzheimer's disease. We studied the impact of amide bond replacements by 1,4-disubstituted 1H-1,2,3-triazoles on the inhibitory activity of the aggregation "hot spots" K16 LVFF20 and G39 VVIA42 in Aß(1-42). We found that peptidotriazolamers act as modulators of the Aß(1-42) oligomerization. Some peptidotriazolamers are able to interfere with the formation of toxic early Aß oligomers, depending on the position of the triazoles, which is also supported by computational studies. Preliminary in vitro results demonstrate that a highly active peptidotriazolamer is also able to cross the blood-brain-barrier.


Asunto(s)
Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/química , Barrera Hematoencefálica/metabolismo , Fragmentos de Péptidos/química , Péptidos/química , Agregado de Proteínas/efectos de los fármacos , Triazoles/química , Amidas/metabolismo , Péptidos beta-Amiloides/metabolismo , Supervivencia Celular , Humanos , Modelos Biológicos , Modelos Moleculares , Conformación Molecular , Estructura Molecular , Fragmentos de Péptidos/metabolismo , Unión Proteica , Relación Estructura-Actividad , Triazoles/metabolismo
18.
Sci Rep ; 9(1): 4893, 2019 03 20.
Artículo en Inglés | MEDLINE | ID: mdl-30894585

RESUMEN

The gelation of L-Tyr(tBu)-OH in tetrahydrofuran (THF) was discovered serendipitously. It was noted that this tremendously low molecular weight (LMW) compound has the ability to gel a wide variety of organic solvents (e.g., N,N-Dimetylformamide (DMF), THF, butanol, toluene), even in very low concentrations (i.e., 0.1 wt/v% in DMF). Addition of bases such as NaOH and piperidine enhanced the gel property. By changing the side-chain protecting group to tert-butyldimethylsilyl (TBDMS), a fluoride ion-responsive organogel was also acquired. This new organogelator responded fluoride ion concentration as low as 0.2 ppm. Characterization of microstructures and gel behaviours were studied by powder X-Ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), rheological measurements and molecular dynamics (MD) simulations. Experimental observations and theoretical simulations consistently show a fibre-like structure of the gel, in which the organogelator molecules are held together via a dense network of hydrogen bonds, and via van der Waals interactions between hydrophobic groups.


Asunto(s)
Furanos/química , Geles/química , Tirosina/química , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Microscopía Electrónica de Transmisión , Simulación de Dinámica Molecular , Peso Molecular , Solventes/química , Difracción de Rayos X
19.
Sci Rep ; 9(1): 6880, 2019 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-31053732

RESUMEN

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

20.
J Mol Model ; 25(7): 197, 2019 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-31222506

RESUMEN

Macrocyclic compounds are of growing interest as a new class of therapeutics, especially as inhibitors binding to protein-protein interfaces. As molecular modeling is a well-established complimentary tool in modern drug design, the number of attempts to develop reliable docking strategies and algorithms to accurately predict the binding mode of macrocycles is rising continuously. Standard molecular docking approaches need to be adapted to this application, as a comprehensive yet efficient sampling of all ring conformations of the macrocycle is necessary. To overcome this issue, we designed a molecular dynamics-based docking protocol for macrocycles, in which the challenging sampling step is addressed by conventional molecular dynamics (750 ns) simulations performed at moderately high temperature (370 K). Consecutive flexible docking with the DynaDock approach based on multiple, pre-sampled ring conformations yields highly accurate poses with ligand RMSD values lower than 1.8 Å. We further investigated the value of molecular dynamics-based complex stability estimations for pose selection and discuss its applicability in combination with standard binding free energy estimations for assessing the quality of poses in future blind docking studies.


Asunto(s)
Compuestos Macrocíclicos/química , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Diseño de Fármacos , Ligandos , Compuestos Macrocíclicos/farmacología , Conformación Molecular , Estructura Molecular , Unión Proteica , Proteínas/química , Relación Estructura-Actividad Cuantitativa , Soluciones
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