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1.
Nature ; 624(7990): 145-153, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37993720

RESUMEN

Gram-negative antibiotic development has been hindered by a poor understanding of the types of compounds that can accumulate within these bacteria1,2. The presence of efflux pumps and substrate-specific outer-membrane porins in Pseudomonas aeruginosa renders this pathogen particularly challenging3. As a result, there are few antibiotic options for P. aeruginosa infections4 and its many porins have made the prospect of discovering general accumulation guidelines seem unlikely5. Here we assess the whole-cell accumulation of 345 diverse compounds in P. aeruginosa and Escherichia coli. Although certain positively charged compounds permeate both bacterial species, P. aeruginosa is more restrictive compared to E. coli. Computational analysis identified distinct physicochemical properties of small molecules that specifically correlate with P. aeruginosa accumulation, such as formal charge, positive polar surface area and hydrogen bond donor surface area. Mode of uptake studies revealed that most small molecules permeate P. aeruginosa using a porin-independent pathway, thus enabling discovery of general P. aeruginosa accumulation trends with important implications for future antibiotic development. Retrospective antibiotic examples confirmed these trends and these discoveries were then applied to expand the spectrum of activity of a gram-positive-only antibiotic, fusidic acid, into a version that demonstrates a dramatic improvement in antibacterial activity against P. aeruginosa. We anticipate that these discoveries will facilitate the design and development of high-permeating antipseudomonals.


Asunto(s)
Antibacterianos , Diseño de Fármacos , Porinas , Pseudomonas aeruginosa , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/farmacología , Escherichia coli/metabolismo , Pruebas de Sensibilidad Microbiana , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/metabolismo , Estudios Retrospectivos , Electricidad Estática , Enlace de Hidrógeno , Ácido Fusídico/metabolismo , Diseño de Fármacos/métodos
2.
Nature ; 604(7906): 546-552, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35228716

RESUMEN

The SARS-CoV-2 Omicron variant exhibits striking immune evasion and is spreading rapidly worldwide. Understanding the structural basis of the high transmissibility and enhanced immune evasion of Omicron is of high importance. Here, using cryo-electron microscopy, we present both the closed and the open states of the Omicron spike (S) protein, which appear more compact than the counterparts of the G614 strain1, potentially related to enhanced inter-protomer and S1-S2 interactions induced by Omicron residue substitution. The closed state showing dominant population may indicate a conformational masking mechanism for the immune evasion of Omicron. Moreover, we captured three states for the Omicron S-ACE2 complex, revealing that the substitutions on the Omicron RBM result in new salt bridges and hydrogen bonds, more favourable electrostatic surface properties, and an overall strengthened S-ACE2 interaction, in line with the observed higher ACE2 affinity of Omicron S than of G614. Furthermore, we determined the structures of Omicron S in complex with the Fab of S3H3, an antibody that is able to cross-neutralize major variants of concern including Omicron, elucidating the structural basis for S3H3-mediated broad-spectrum neutralization. Our findings shed light on the receptor engagement and antibody neutralization or evasion of Omicron and may also inform the design of broadly effective vaccines against SARS-CoV-2.


Asunto(s)
COVID-19 , Glicoproteína de la Espiga del Coronavirus , Enzima Convertidora de Angiotensina 2 , Anticuerpos Antivirales , Vacunas contra la COVID-19 , Microscopía por Crioelectrón , Humanos , SARS-CoV-2
3.
Nano Lett ; 24(17): 5351-5360, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38634773

RESUMEN

Ultrasensitive and reliable conductive hydrogels are significant in the construction of human-machine twinning systems. However, in extremely cold environments, freezing severely limits the application of hydrogel-based sensors. Herein, building on biomimetics, a zwitterionic hydrogel was elaborated for human-machine interaction employing multichemical bonding synergies and experimental signal analyses. The covalent bonds, hydrogen bonds, and electrostatic interactions construct a dense double network structure favorable for stress dispersion and hydrogen bond regeneration. In particular, zwitterions and ionic conductors maintained excellent strain response (99 ms) and electrical sensitivity (gauge factor = 14.52) in the dense hydrogel structure while immobilizing water molecules to enhance the weather resistance (-68 °C). Inspired by the high sensitivity, zwitterionic hydrogel-based strain sensors and remote-control gloves were designed by analyzing the experimental signals, demonstrating promising potential applications within specialized flexible materials and human-machine symbiotic systems.


Asunto(s)
Hidrogeles , Hidrogeles/química , Humanos , Dispositivos Electrónicos Vestibles , Congelación , Enlace de Hidrógeno , Electricidad Estática , Conductividad Eléctrica
4.
Inorg Chem ; 63(26): 12342-12349, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38904258

RESUMEN

As a typical RNA virus, the genetic information on HIV-1 is entirely stored in RNA. The reverse transcription activity of HIV-1 reverse transcriptase (RT) plays a crucial role in the replication and transmission of the virus. Non-nucleoside RT inhibitors (NNRTIs) block the function of RT by binding to the RNA binding site on RT, with very few targeting viral RNA. In this study, by transforming planar conjugated ligands into a spiro structure, we convert classical Ru(II) DNA intercalators into a nonintercalator. This enables selective binding to HIV-1 transactivation response (TAR) RNA on the outer side of nucleic acids through dual interactions involving hydrogen bonds and electrostatic attraction, effectively inhibiting HIV-1 RT and serving as a selective fluorescence probe for TAR RNA.


Asunto(s)
Transcriptasa Inversa del VIH , VIH-1 , Inhibidores de la Transcriptasa Inversa , Rutenio , Transcriptasa Inversa del VIH/antagonistas & inhibidores , Transcriptasa Inversa del VIH/metabolismo , Inhibidores de la Transcriptasa Inversa/química , Inhibidores de la Transcriptasa Inversa/farmacología , Inhibidores de la Transcriptasa Inversa/metabolismo , Ligandos , VIH-1/enzimología , VIH-1/efectos de los fármacos , Rutenio/química , Rutenio/farmacología , ARN Viral/metabolismo , ARN Viral/química , Compuestos de Espiro/química , Compuestos de Espiro/farmacología , Compuestos de Espiro/metabolismo , Complejos de Coordinación/química , Complejos de Coordinación/farmacología , Complejos de Coordinación/síntesis química , Sustancias Intercalantes/química , Sustancias Intercalantes/farmacología , Estructura Molecular , Humanos , Fármacos Anti-VIH/química , Fármacos Anti-VIH/farmacología , Duplicado del Terminal Largo de VIH , Sitios de Unión
5.
Phys Chem Chem Phys ; 26(25): 17549-17560, 2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38884195

RESUMEN

In this paper, we combine an energy decomposition analysis (EDA) scheme with many-body expansion (MBE) to develop a MB-EDA method to study the cooperative and anti-cooperative effects in molecular cluster systems. Based on the target state optimization self-consistent field (TSO-SCF) method, the intermolecular interaction energy can be decomposed into five chemically meaningful terms, i.e., electrostatic, exchange, polarization, charge transfer and dispersion interaction energies. MB-EDA can decompose each of these terms in MBE. This MB-EDA has been applied to 3 different cluster systems: water clusters, ionic liquid clusters, and acetonitrile-methane clusters. This reveals that electrostatic, exchange, and dispersion interactions are highly pairwise additive in all systems. In water and ionic liquid clusters, the many-body effects are significant in both polarization and charge transfer interactions, but are cooperative and anti-cooperative, respectively. For acetonitrile-methane clusters, which do not involve hydrogen bonds or charge-charge Coulombic interactions, the many-body effects are quite small. The chemical origins of different many-body effects are deeply analyzed. The MB-EDA method has been implemented in Qbics (https://qbics.info) and can be a useful tool for understanding the many-body behavior in molecular aggregates at the quantum chemical level of theory.

6.
Phys Chem Chem Phys ; 26(34): 22726-22738, 2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39161312

RESUMEN

Matrix protein 2 (M2) and matrix protein 1 (M1) of the influenza B virus are two important proteins, and the interactions between BM2 and BM1 play an important role in the process of virus assembly and replication. However, the interaction details between BM2 and BM1 are still unclear at the atomic level. Here, we constructed the BM2-BM1 complex system using homology modelling and molecular docking methods. Molecular dynamics (MD) simulations were used to illustrate the binding mechanism between BM2 and BM1. The results identify that the eight polar residues (E88B, E89B, H119BM1, E94B, R101BM1, K102BM1, R105BM1, and E104B) play an important role in stabilizing the binding through the formation of hydrogen bond networks and salt-bridge interactions at the binding interface. Furthermore, based on the simulation results and the experimental facts, the mutation experiments were designed to verify the influence of the mutation of residues both within and outside the effector domain. The mutations directly or indirectly disrupt interactions between polar residues, thus affecting viral assembly and replication. The results could help us understand the details of the interactions between BM2 and BM1 and provide useful information for the anti-influenza drug design.


Asunto(s)
Simulación de Dinámica Molecular , Unión Proteica , Electricidad Estática , Proteínas de la Matriz Viral , Proteínas de la Matriz Viral/química , Proteínas de la Matriz Viral/metabolismo , Virus de la Influenza B/química , Virus de la Influenza B/metabolismo , Enlace de Hidrógeno , Simulación del Acoplamiento Molecular , Mutación , Sitios de Unión , Proteínas Virales
7.
Phys Chem Chem Phys ; 26(39): 25480-25487, 2024 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-39324232

RESUMEN

In this study, molecular dynamics simulations were used to systematically explore the reason why BH3-only protein BAD binds to anti-apoptotic protein BCL-xL but not to MCL-1 to give more theoretical hints for the design of BAD mimetic inhibitors for the dual-targeting of BCL-xL and MCL-1. Starting with the difference in residue-based binding energy contributions, a series of analyses were conducted to identify the hotspot residues in MCL-1 that significantly affect the interaction with BAD. Among them, the insertion of the T residue in the loop between α4 and α5 domains of MCL-1 is considered to be the main cause of BAD selective binding. The inserted T residue reduces the stability of the loop and weakens the hydrogen bond interactions that originally bound E19 of BAD in BCL-xL/BAD, and the freed E19 severely interferes with the salt bridge between D16 and Arg53 by electrostatic repulsion. This salt-bridge is believed to be critical for maintaining the binding between BCL-xL and BAD. By clarifying the reasons for differential binding, we can more specifically optimize the BAD sequence to target both BCL-xL and MCL-1.


Asunto(s)
Simulación de Dinámica Molecular , Proteína 1 de la Secuencia de Leucemia de Células Mieloides , Unión Proteica , Proteína Letal Asociada a bcl , Proteína bcl-X , Proteína bcl-X/química , Proteína bcl-X/metabolismo , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/química , Proteína Letal Asociada a bcl/metabolismo , Proteína Letal Asociada a bcl/química , Humanos , Enlace de Hidrógeno , Sitios de Unión
8.
J Chem Phys ; 161(1)2024 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-38949586

RESUMEN

Water confined within nanochannels with specific functionalities serves as the foundation for a variety of emerging nanofluidic applications. However, the structure and dynamics of the confined liquid are susceptibly influenced by practically hard-to-avoid defects, yet knowledge of this fact remains largely unexplored. Here, using extensive molecular dynamics simulations, we elucidate the significant influence of geometric and charge defects on one-dimensional confined water. We show that the two types of defects can both reshape the water density distribution by constraining the translocation of water molecules along the circumferential direction. In addition to structural alterations, collective translocation and rotation of water slabs arise during transportation under external pressure. Below the temperature threshold marking the initiation of liquid-solid transition, the geometric defect retards water diffusion through a pinning effect, while the charge defect induces an anti-freezing effect. The latter is attributed to the electrostatic interaction between the charge defect and water molecules that hinders the formation of a stable hydrogen bond network by disrupting molecular dipole orientation. Consequently, this behavior results in a reduction in the number and lifetime of hydrogen bonds within the phase transition interval. The distinct roles of the two types of defects could be utilized to control the structure and dynamics of confined liquids that may result in distinct functionalities for nanofluidic applications.

9.
J Nanobiotechnology ; 22(1): 439, 2024 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-39061033

RESUMEN

Skin wound infection has become a notable medical threat. Herein, the polysaccharide-based injectable hydrogels with multifunctionality were developed by a simple and fast gelation process not only to inactivate bacteria but also to accelerate bacteria-infected wound healing. Sodium nitroprusside (SNP) loaded PCN-224 nanoparticles were introduced into the polymer matrix formed by the dynamic and reversible coordinate bonds between Ag+ with carboxyl and amino or hydroxyl groups on carboxymethyl chitosan (CMCS), hydrogen bonds and electrostatic interactions in the polymer to fabricate SNP@PCN@Gel hydrogels. SNP@PCN@Gel displayed interconnected porous structure, excellent self-healing capacity, low cytotoxicity, good blood compatibility, and robust antibacterial activity. SNP@PCN@Gel could produce reactive oxygen species (ROS) and NO along with Fe2+, and showed long-term sustained release of Ag+, thereby effectively killing bacteria by synergistic photothermal (hyperthermia), photodynamic (ROS), chemodynamic (Fenton reaction), gas (NO) and ion (Ag+ and -NH3+ in CMCS) therapy. Remarkably, the hydrogels significantly promoted granulation tissue formation, reepithelization, collagen deposition and angiogenesis as well as wound contraction in bacteria-infected wound healing. Taken together, the strategy represented a general method to engineer the unprecedented photoactivatable "all-in-one" hydrogels with enhanced antibacterial activity and paved a new way for development of antibiotic alternatives and wound dressing.


Asunto(s)
Antibacterianos , Quitosano , Hidrogeles , Cicatrización de Heridas , Hidrogeles/química , Hidrogeles/farmacología , Cicatrización de Heridas/efectos de los fármacos , Antibacterianos/farmacología , Antibacterianos/química , Quitosano/química , Quitosano/análogos & derivados , Quitosano/farmacología , Animales , Nitroprusiato/farmacología , Nitroprusiato/química , Ratones , Especies Reactivas de Oxígeno/metabolismo , Humanos , Plata/química , Plata/farmacología , Nanopartículas/química , Infección de Heridas/tratamiento farmacológico , Escherichia coli/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos
10.
Luminescence ; 39(9): e4869, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39192755

RESUMEN

In the present study, the drug delivery by albumin protein and antiproliferetaive activity of new transition metal complex i.e., [Pd (phen)(SSA)] (where phen and SSA represent 1, 10 phenanthroline and sulfosalicylic acid, respectively) was investigated. DFT (density functional theory) calculations were conducted at B3LYP level with 6-311G(d,p)/aug-ccpVTZ-PP basis set for the purpose of geometry optimization, frontier molecular orbital (FMO) analysis, molecular electrostatic potential (MEP), and natural bond orbital (NBO) analysis. Experimental tests were conducted to preliminarily assess the lipophilicity and antitumor activity of the metal complex, resulting in promising findings. In-silico prediction was accomplished to assess its toxicity and bioavailability. To evaluate the binding of the newly formed complex with DNA (which results in halting the cell cycle) or serum albumin protein (drug transporter to the tissues), in-silico molecular modeling was employed. Experimental results (spectroscopic and non-spectroscopic) showed that the new compound interacts with each biomolecule via hydrogen bond and van der Waals interactions. Molecular docking demonstrated the binding of this complex to the DNA groove and site I of BSA occurs mainly through hydrogen bonds. Molecular dynamics simulation confirmed the interactions between [Pd (phen)(SSA)] with DNA or BSA through stable hydrogen bonds.


Asunto(s)
Antineoplásicos , Simulación del Acoplamiento Molecular , Salicilatos , Antineoplásicos/química , Antineoplásicos/farmacología , Salicilatos/química , Salicilatos/farmacología , Humanos , Teoría Funcional de la Densidad , Complejos de Coordinación/química , Complejos de Coordinación/farmacología , Albúmina Sérica Bovina/química , Albúmina Sérica Bovina/metabolismo , Estructura Molecular , Ensayos de Selección de Medicamentos Antitumorales , Fenantrolinas/química , Fenantrolinas/farmacología , Animales , Proliferación Celular/efectos de los fármacos , Línea Celular Tumoral , ADN/química , ADN/metabolismo , Bencenosulfonatos
11.
Chem Biodivers ; 21(10): e202400752, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38923373

RESUMEN

Myricetin (1), Quercetin (2), Kaempferol (3) and Kaempferide (4) were flavonoids with phenolic hydroxyl groups. The antioxidant and pharmacological mechanisms of them were investigated in detail. The lowest hydroxyl dissociation enthalpies of 1, 2, 3 and 4 were calculated by DFT, respectively. The hydroxyl dissociation enthalpies of the four flavonoids at the O2 site are the highest. By analyzing the intramolecular hydrogen bonds and HOMO-LUMO orbitals of the four flavonoids, the reasons for their divergence of hydroxyl dissociation enthalpies and antioxidant mechanisms were further investigated. The UV-vis and IR spectra of four flavonoids were compared. The interactions about electrostatic attraction, p-π conjugation and hydrogen bond combined the flavonoid with the target protein closely. The root mean square deviation of peroxisome proliferator-activated receptor γ combined with 1, 2 and 3 increased, while that of PPARγ combined with 4 decreased.


Asunto(s)
Antioxidantes , Teoría Funcional de la Densidad , Flavonoides , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , PPAR gamma , Flavonoides/química , Flavonoides/farmacología , Antioxidantes/química , Antioxidantes/farmacología , PPAR gamma/metabolismo , PPAR gamma/química , Quempferoles/química , Quempferoles/farmacología , Quercetina/química , Quercetina/farmacología , Humanos , Termodinámica , Enlace de Hidrógeno , Espectrofotometría Ultravioleta , Estructura Molecular , Compuestos de Bifenilo/antagonistas & inhibidores , Compuestos de Bifenilo/química , Espectrofotometría Infrarroja
12.
Int J Mol Sci ; 25(11)2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38891796

RESUMEN

Among various non-covalent interactions, selenium-centered chalcogen bonds (SeChBs) have garnered considerable attention in recent years as a result of their important contributions to crystal engineering, organocatalysis, molecular recognition, materials science, and biological systems. Herein, we systematically investigated π-hole-type Se∙∙∙O/S ChBs in the binary complexes of SeO2 with a series of O-/S-containing Lewis bases by means of high-level ab initio computations. The results demonstrate that there exists an attractive interaction between the Se atom of SeO2 and the O/S atom of Lewis bases. The interaction energies computed at the MP2/aug-cc-pVTZ level range from -4.68 kcal/mol to -10.83 kcal/mol for the Se∙∙∙O chalcogen-bonded complexes and vary between -3.53 kcal/mol and -13.77 kcal/mol for the Se∙∙∙S chalcogen-bonded complexes. The Se∙∙∙O/S ChBs exhibit a relatively short binding distance in comparison to the sum of the van der Waals radii of two chalcogen atoms. The Se∙∙∙O/S ChBs in all of the studied complexes show significant strength and a closed-shell nature, with a partially covalent character in most cases. Furthermore, the strength of these Se∙∙∙O/S ChBs generally surpasses that of the C/O-H∙∙∙O hydrogen bonds within the same complex. It should be noted that additional C/O-H∙∙∙O interactions have a large effect on the geometric structures and strength of Se∙∙∙O/S ChBs. Two subunits are connected together mainly via the orbital interaction between the lone pair of O/S atoms in the Lewis bases and the BD*(OSe) anti-bonding orbital of SeO2, except for the SeO2∙∙∙HCSOH complex. The electrostatic component emerges as the largest attractive contributor for stabilizing the examined complexes, with significant contributions from induction and dispersion components as well.


Asunto(s)
Calcógenos , Bases de Lewis , Oxígeno , Selenio , Azufre , Bases de Lewis/química , Calcógenos/química , Selenio/química , Azufre/química , Oxígeno/química , Modelos Moleculares , Enlace de Hidrógeno , Óxidos de Selenio/química , Termodinámica
13.
Molecules ; 29(16)2024 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-39203016

RESUMEN

Herein, we report a new strategy for the design of antibiotic agents based on the electrostatic interaction and hydrogen bonding, highlighting the significance of hydrogen bonding and the increased recognition sites in facilitating the interaction with bacterial cell membranes and DNA. A series of quaternary ammonium functionalized urea-based anion receptors were studied. While the monodentate mono-urea M1, bisurea M2, and trisurea M3 failed to break through the cell membrane barrier and thus could not kill bacteria, the extended bidentate dimers D1-D3 presented gradually increased membrane penetrating capabilities, DNA conformation perturbation abilities, and broad-spectrum antibacterial activities against E. coli, P. aeruginosa, S. aureus, E. faecalis, and S. epidermidis.


Asunto(s)
Antibacterianos , Membrana Celular , Enlace de Hidrógeno , Urea , Urea/química , Urea/farmacología , Antibacterianos/farmacología , Antibacterianos/química , Membrana Celular/metabolismo , Membrana Celular/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , ADN Bacteriano/metabolismo , Bacterias/efectos de los fármacos , Bacterias/metabolismo , Compuestos de Amonio Cuaternario/química , Compuestos de Amonio Cuaternario/farmacología , Escherichia coli/efectos de los fármacos
14.
J Sci Food Agric ; 104(11): 6573-6583, 2024 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-38520286

RESUMEN

BACKGROUND: Pectin extracted by high-speed shearing from passion fruit peel (HSSP) is a potentially excellent wall material for encapsulating curcumin, which has multiple advantages over pectin prepared by heated water extraction. HSSP was used to fabricate complex nanoparticles of zein-sodium caseinate-pectin for encapsulation of curcumin in this study. The influence of heating on the physicochemical properties of the composite nanoparticles was also investigated, as well as the effect of composite nanoparticles on the encapsulation efficiency, antioxidant activity and release characteristics of curcumin. RESULTS: The nanoparticles were formed through electrostatic interactions, hydrogen bonds and hydrophobic interactions between the proteins and HSSP. A temperature of 50 °C was more favorable for generating compact and small-sized nanoparticles, which could effectively improve the encapsulation efficiency and functional properties. Moreover, compared to other pectin used in the study, the nanoparticles prepared with HSSP showed the best functionality with a particle size of 234.28 ± 0.85 nm, encapsulation rate of 90.22 ± 0.54%, free radical scavenging rate of 78.97% and strongest protective capacity in simulated gastric fluid and intestinal release effect. CONCLUSION: Zein-sodium caseinate-HSSP is effective for encapsulating and delivering hydrophobic bioactive substances such as curcumin, which has potential applications in the functional food and pharmaceutical industries. © 2024 Society of Chemical Industry.


Asunto(s)
Caseínas , Curcumina , Composición de Medicamentos , Frutas , Nanopartículas , Tamaño de la Partícula , Passiflora , Pectinas , Zeína , Pectinas/química , Passiflora/química , Zeína/química , Caseínas/química , Curcumina/química , Nanopartículas/química , Frutas/química , Extractos Vegetales/química , Interacciones Hidrofóbicas e Hidrofílicas , Portadores de Fármacos/química , Antioxidantes/química
15.
Biochemistry ; 62(12): 1890-1905, 2023 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-37246507

RESUMEN

The mechanism of protein aggregation can be broadly viewed as a shift from the native-state stabilizing intramolecular to the aggregated-phase sustaining intermolecular interactions. Understanding the role of electrostatic forces on the extent of modulation of this switch has recently evolved as a topic of monumental significance as protein aggregation has lately been connected to charge modifications of an aging proteome. To decipher the distinctive role of electrostatic forces on the extremely complicated phase separation landscape, we opted for a combined in vitro-in silico approach to ascertain the structure-dynamics-stability-aggregability relationship of the functional tandem RRM domains of the ALS-related protein TDP-43 (TDP-43tRRM), under a bivariate solution condition in terms of pH and salt concentration. Under acidic pH conditions, the native TDP-43tRRM protein creates an aggregation-prone entropically favorable partially unfolded conformational landscape due to enthalpic destabilization caused by the protonation of the buried ionizable residues and consequent overwhelming fluctuations of selective segments of the sequence leading to anti-correlated movements of the two domains of the protein. The evolved fluffy ensemble with a comparatively exposed backbone then easily interacts with incoming protein molecules in the presence of salt via typical amyloid-aggregate-like intermolecular backbone hydrogen bonds with a considerable contribution originating from the dispersion forces. Subsequent exposure to excess salt at low pH conditions expedites the aggregation process via an electrostatic screening mechanism where salt shows preferential binding to the positively charged side chain. The applied target observable-specific approach complementarity unveils the hidden information landscape of an otherwise complex process with unquestionable conviction.


Asunto(s)
Amiloide , Agregado de Proteínas , Electricidad Estática , Amiloide/química , Proteínas Amiloidogénicas , Proteínas de Unión al ADN/química , Pliegue de Proteína
16.
J Chem Inf Model ; 63(16): 5297-5308, 2023 08 28.
Artículo en Inglés | MEDLINE | ID: mdl-37586058

RESUMEN

The Omicron lineage of SARS-CoV-2, which was first reported in November 2021, has spread globally and become dominant, splitting into several sublineages. Experiments have shown that Omicron lineage has escaped or reduced the activity of existing monoclonal antibodies, but the origin of escape mechanism caused by mutation is still unknown. This work uses molecular dynamics and umbrella sampling methods to reveal the escape mechanism of BA.1.1 to monoclonal antibody (mAb) Tixagevimab (AZD1061) and BA.5 to mAb Cilgavimab (AZD8895), both mAbs were combined to form antibody cocktail, Evusheld (AZD7442). The binding free energy of BA.1.1-AZD1061 and BA.5-AZD8895 has been severely reduced due to multiple-site mutated Omicron variants. Our results show that the two Omicron variants, which introduce a substantial number of positively charged residues, can weaken the electrostatic attraction between the receptor binding domain (RBD) and AZD7442, thus leading to a decrease in affinity. Additionally, using umbrella sampling along dissociation pathway, we found that the two Omicron variants severely impaired the interaction between the RBD of SARS-CoV-2's spike glycoprotein (S protein) and complementary determining regions (CDRs) of mAbs, especially in CDR3H. Although mAbs AZD8895 and AZD1061 are knocked out by BA.5 and BA.1.1, respectively, our results confirm that the antibody cocktail AZD7442 retains activity against BA.1.1 and BA.5 because another antibody is still on guard. The study provides theoretical insights for mAbs interacting with BA.1.1 and BA.5 from both energetic and dynamic perspectives, and we hope this will help in developing new monoclonals and combinations to protect those unable to mount adequate vaccine responses.


Asunto(s)
COVID-19 , Evasión Inmune , COVID-19/inmunología , Simulación por Computador , Humanos , Anticuerpos Antivirales/química , Anticuerpos Antivirales/inmunología , Modelos Moleculares , Estructura Cuaternaria de Proteína , Estructura Terciaria de Proteína , Enlace de Hidrógeno
17.
Phys Chem Chem Phys ; 25(17): 12284-12289, 2023 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-37078898

RESUMEN

A 512 cage of (H2O)20 consisting of 30 hydrogen bonds encapsulates Astatide with little geometrical distortion. The cage is marginally destabilized but the non-covalent interactions are actually strengthened. Host⋯cage interactions in the [At@(H2O)20]- cluster are anti-electrostatic, placing both negatively charged atoms in direct contact as in Atδ-⋯δ-O-Hδ+. An orbital interaction analysis reveals that explicit host⋯cage contacts are "inverted" hydrogen bonds. That is, the same type of donor→acceptor charge transfer as in hydrogen bonding, with no proton bridging the two negative charges.

18.
Environ Res ; 231(Pt 3): 116307, 2023 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-37268205

RESUMEN

The pollution problem of oxytetracycline (OTC) from wastewater becomes more serious, so an efficient, economical, and green adsorption material is urgently explored. In this study, the multilayer porous biochar (OBC) was prepared by coupling carbon nanotubes with iron oxide nanoparticles synthesized by Aquabacterium sp. XL4 to modify corncobs under medium temperature (600 °C) conditions. The adsorption capacity of OBC could reach 72.59 mg g-1 after preparation and operation parameters were optimized. In addition, various adsorption models suggested that OTC removal resulted from the combined effect of chemisorption, multilayer interaction, and disordered diffusion. Meanwhile, the OBC was fully characterized and exhibited a large specific surface area (237.51 m2 g-1), abundant functional groups, stable crystal structure, high graphitization, and mild magnetic properties (0.8 emu g-1). The OTC removal mechanisms mainly included electrostatic interactions, ligand exchange, π-π bonding reactions, hydrogen bonds, and complexation. pH and coexistence substance experiments revealed that the OBC possesses a wide pH adaptation range and excellent anti-interference ability. Finally, the safety and reusability of OBC were confirmed by repeated experiments. In summary, OBC as a biosynthetic material shows considerable potential for application in the field of purifying new pollution from wastewater.


Asunto(s)
Nanotubos de Carbono , Oxitetraciclina , Contaminantes Químicos del Agua , Oxitetraciclina/química , Aguas Residuales , Adsorción , Nanopartículas Magnéticas de Óxido de Hierro , Contaminantes Químicos del Agua/análisis , Cinética
19.
Proc Natl Acad Sci U S A ; 117(25): 13967-13974, 2020 06 23.
Artículo en Inglés | MEDLINE | ID: mdl-32503918

RESUMEN

Molecular dynamics and free energy simulations have been carried out to elucidate the structural origin of differential protein-protein interactions between the common receptor protein angiotensin converting enzyme 2 (ACE2) and the receptor binding domains of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [A. E. Gorbalenya et al., Nat. Microbiol. 5, 536-544 (2020)] that causes coronavirus disease 2019 (COVID-19) [P. Zhou et al., Nature 579, 270-273 (2020)] and the SARS coronavirus in the 2002-2003 (SARS-CoV) [T. Kuiken et al., Lancet 362, 263-270 (2003)] outbreak. Analysis of the dynamic trajectories reveals that the binding interface consists of a primarily hydrophobic region and a delicate hydrogen-bonding network in the 2019 novel coronavirus. A key mutation from a hydrophobic residue in the SARS-CoV sequence to Lys417 in SARS-CoV-2 creates a salt bridge across the central hydrophobic contact region, which along with polar residue mutations results in greater electrostatic complementarity than that of the SARS-CoV complex. Furthermore, both electrostatic effects and enhanced hydrophobic packing due to removal of four out of five proline residues in a short 12-residue loop lead to conformation shift toward a more tilted binding groove in the complex in comparison with the SARS-CoV complex. On the other hand, hydrophobic contacts in the complex of the SARS-CoV-neutralizing antibody 80R are disrupted in the SARS-CoV-2 homology complex model, which is attributed to failure of recognition of SARS-CoV-2 by 80R.


Asunto(s)
Betacoronavirus/fisiología , Peptidil-Dipeptidasa A/metabolismo , Unión Proteica , Receptores Virales/metabolismo , Aminoácidos/química , Enzima Convertidora de Angiotensina 2 , Anticuerpos Neutralizantes/metabolismo , Anticuerpos Antivirales/metabolismo , COVID-19 , Infecciones por Coronavirus , Humanos , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Modelos Moleculares , Simulación de Dinámica Molecular , Pandemias , Neumonía Viral , Dominios Proteicos , SARS-CoV-2 , Electricidad Estática
20.
Int J Mol Sci ; 24(3)2023 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-36768510

RESUMEN

Carbamazepine (CBZ), a commonly prescribed antiepileptic drug, in human liver, is mainly metabolized by two isoforms of cytochrome P450 (CYP), CYP3A4 and CYP3A5. Therefore, the binding of CBZ with these two enzymes plays crucial role in the biotransformation of the drug into its active metabolite. In the present work, classical molecular dynamics (MD) simulation was used to investigate the detailed interaction mechanism between CBZ and these two CYP isoforms at the atomic level. The results revealed that although CBZ can bind with the two proteins, all kinds of the interactions, including hydrogen bonds, salt bridges, hydrophobic interaction, and π-π interaction, are isoform specific. The specificity directly leads to a binding environment difference at the active sites of the two isoforms, as represented by the electrostatic surface potential maps, which further results in the varied dynamic behavior of CBZ in the two isoforms. Our research will help to deepen the understanding of the physiological functions of CYP isoforms and opens the door for the rational design and development of isoform-specific inhibitors.


Asunto(s)
Carbamazepina , Citocromo P-450 CYP3A , Humanos , Citocromo P-450 CYP3A/metabolismo , Carbamazepina/química , Sistema Enzimático del Citocromo P-450/metabolismo , Anticonvulsivantes/farmacología , Benzodiazepinas , Isoformas de Proteínas
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