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The CRISPR-Cas9 technology used in plant biotechnology is based on the use of Cas9 endonucleases to generate precise cuts in the genome, and a duplex consisting of a trans-activating CRISPR RNA (tracrRNA) and a CRISPR RNA (DRRNA) which are precursors of guide RNA (sgRNA) commercially redesigned (sgRNA-Cas9) to guide gene cleavage. Most of these tools come from clinical bacteria. However, there are several CRISPR-Cas9 systems in environmental microorganisms such as phytoendosymbionts of plants of the genus Acholeplasma. But the exploitation of these systems more compatible with plants requires using bioinformatics tools for prediction and study. We identified and characterized the elements associated with the duplex in the genome of A. palmae. For this, the protein information was obtained from the Protein Data Bank and the genomics from GenBank/NCBI. The CRISPR system was studied with the CRISPRfinder software. Alignment algorithms and NUPACK software were used to identify the tracrRNA and DRRNA modules, together with various computational software for genetic, structural and biophysical characterization. A CRISPR-Cas system was found in A. palmae with type II-C characteristics, as well as a thermodynamically very stable duplex, with flexible regions, exhibiting a docking power with Cas9 thermodynamically favored. These results are desirable in programmable gene editing systems and show the possibility of exploring native molecular tools in environmental microorganisms applicable to the genetic manipulation of plants, as more research is carried out. This study represents the first report on the thermodynamic stability and molecular docking of elements associated with the tracrRNA-DRRNA duplex in the phytosymbiont A. palmae.

We determined the optical profiles of a molecular system coupled with a thermal bath in presence of intramolecular coupling. Solvent effects were explicitly considered as a random variable by model...

The pandemic caused by SARS-CoV-2 forces drug research to combat it. Ivermectin, an FDA approved antiparasitic drug formulated as a mixture 80:20 of the equipotent homologous 22,23 dihydro ivermectin (B1_a and B1_b), which is known to inhibit SARS-CoV-2 in vitro with a mechanism of action to be defined. It draws attention powerfully that the energetic and structural perturbation that this drug induces by binding on SARS-COV-2 proteins of importance for its proliferation is ill unknown. Hence what we do an exhaustive computational biophysics study to discriminate the best docking of ivermectins to viral proteins and, subsequently, to analyze possible structural alterations with molecular dynamics. The results suggested that ivermectins are capable of docking to the superficial and internal pocket of the 3CL-protease and the HR2-domain, inducing unfolding/folding that change the native conformation in these proteins. In particular, ivermectin binds to the 3CL protease and leads this protein to an unfolded state, whereas the HR2-domain to a more compact conformation in comparison to the native state by refolding when the drug binding to this protein. The results obtained suggest a possible synergistic inhibitory against SARS-COV-2 owing to each role of ivermectins when favorably binding to these viral proteins. Given the importance of the results obtained about this new mechanism of action of ivermectin on SARS-CoV-2, experimental studies are needed that corroborate this proposal.

The topological profiles of the nonlinear optical properties of a two-level molecular system involving simplified versions of intramolecular coupling immersed in a thermal reservoir have been studied in four-wave mixing (FWM) spectroscopy. Solvent effects have been explicitly considered by modeling the nonradiative interaction with the solute as a random variable. To formulate a solution, it is necessary to introduce stochastic considerations. We assume that system–solvent interactions induce random shifts in the Bohr frequency of the adiabatic states, and their manifestation corresponds to the broadening of the upper level. The Born–Oppenheimer (BO) electronic energy curves for this molecular model consist of two intertwined harmonic oscillator potentials shifted in both their position and their minimum equilibrium energy. The critical quantities for this analysis are the transition and permanent dipole moments, which depend strongly on intramolecular coupling. Our results show how absorption and refractive index are affected by vibronic coupling and solvent stochasticity.

The SARS-CoV-2 pandemic has accelerated the study of existing drugs. The mixture of homologs called ivermectin (avermectin-B1a [HB1a] + avermectin-B1b [HB1b]) has shown antiviral activity against SARS-CoV-2 in vitro. However, there are few reports on the behavior of each homolog. We investigated the interaction of each homolog with promising targets of interest associated with SARS-CoV-2 infection from a biophysical and computational-chemistry perspective using docking and molecular dynamics. We observed a differential behavior for each homolog, with an affinity of HB1b for viral structures, and of HB1a for host structures considered. The induced disturbances were differential and influenced by the hydrophobicity of each homolog and of the binding pockets. We present the first comparative analysis of the potential theoretical inhibitory effect of both avermectins on biomolecules associated with COVID-19, and suggest that ivermectin through its homologs, has a multiobjective behavior., Graphical abstract Unlabelled Image

The COVID-19 pandemic has accelerated the study of the potential of multi-target drugs (MTDs). The mixture of homologues called ivermectin (avermectin-B1a + avermectin-B1b) has been shown to be a MTD with potential antiviral activity against SARS-CoV-2 in vitro. However, there are few reports on the effect of each homologue on the flexibility and stiffness of proteins associated with COVID-19, described as ivermectin targets. We observed that each homologue was stably bound to the proteins studied and was able to induce detectable changes with Elastic Network Models (ENM). The perturbations induced by each homologue were characteristic of each compound and, in turn, were represented by a disruption of native intramolecular networks (interactions between residues). The homologues were able to slightly modify the conformation and stability of the connection points between the Cα atoms of the residues that make up the structural network of proteins (nodes), compared to free proteins. Each homologue was able to modified differently the distribution of quasi-rigid regions of the proteins, which could theoretically alter their biological activities. These results could provide a biophysical-computational view of the potential MTD mechanism that has been reported for ivermectin.

SARS-CoV-2 has caused millions of infections and more than 600,000 deaths worldwide Despite the large number of studies to date, there is no specifically effective treatment available for SARS-CoV-2 However, it has been proposed to target reused drugs with potential antiviral activity to the interface between the angiotensin-converting enzymes 2 (ACE2) and the receptor binding domain (RBD) of SARS-CoV-2 to avoid cell recognition Some non-steroidal anti-inflammatory drugs (NSAIDs) have been reported to have some type of activity against a wide variety of viruses including SARS-CoV-2 Therefore, we carried out an exhaustive computational biophysical study of various NSAIDs targeting the RBD-ACE2 complex using multiple comparative analysis of docking and molecular dynamics Only the Ibuprofen (Propionic acid derivative), Aspirin (Salicylate), and the Acetaminophen (p-aminophenol derivative) had a thermodynamically favorable docking with the interface of the RBD-ACE2 complex under the conditions of this study Although, Ibuprofen was the NSAIDs with the most thermodynamically favorable docking in the shortest simulation time, and was the major inducer of structural changes, conformational changes, and overall changes in the complex throughout the simulation, including disturbances in composition and distribution of cavities at the interface Results that point to Ibuprofen as an NSAID that, under the conditions outlined in this investigation, may have the highest probability of generating a disturbance in the stability of the RBD-ACE2 complex This statement, although it could contribute information for the empirical treatment and prevention of COVID-19, represents only a theoretical orientation and approach, and requires its experimental demonstration because our predictions cannot secure a pharmacologically and clinically relevant interaction However, these results are relevant due that suggest a possible mechanism of action of Ibuprofen against COVID-19 in addition to its anti-inflammatory properties, of which there are no reports in the literature © Copyright © 2020 Gonzalez-Paz, Lossada, Fernandez-Materan, Paz, Vera-Villalobos and Alvarado

The global pandemic caused by infections of the new coronavirus (COVID-19) makes it necessary to find possible less toxic and easily accessible therapeutic agents. In this study, we used strategies docking and molecular dynamics to analyze phytochemical compounds against FDA-approved antimalarial drugs recommended for the treatment of COVID-19. The evaluation was performed with the docking scores MolDock Score and Rerank Score calculated by Molegro Molecular. The DockThor server was used to generate the complexes and myPresto for the dynamic studies. Preliminary results suggested that piperine, capsaicin, and curcumin have the best docking scores and that they are capable of promoting structural changes in the viral protease by inducing folding of the enzyme. Curcumin and capsaicin bring the enzyme to a more compact conformational state compared to the native state, compared to chloroquine. Even though, it is unknown if these induced changes in protease are related to any inhibitory effect observed both in vitro and in vivo for any of these compounds. Further studies on the mechanisms of action of these compounds of interest are required, as well as experimental demonstrations. However, these results are interesting because they can serve as a starting point for subsequent experimental or/and in silico studies based on chemical structure-activity relationships taking these small molecules and their possible derivatives.