Conserved recombination patterns across coronavirus subgenera (preprint)

Recombination contributes to the genetic diversity found in coronaviruses and is known to be a prominent mechanism whereby they evolve. It is apparent, both from controlled experiments and in genome sequences sampled from nature, that patterns of recombination in coronaviruses are non-random and that this is likely attributable to a combination of sequence features that favour the occurrence of recombination breakpoints at specific genomic sites, and selection disfavouring the survival of recombinants within which favourable intra-genome interactions have been disrupted. Here we leverage available whole-genome sequence data for six coronavirus subgenera to identify specific patterns of recombination that are conserved between multiple subgenera and then identify the likely factors that underlie these conserved patterns. Specifically, we confirm the non-randomness of recombination breakpoints across all six tested coronavirus subgenera, locate conserved recombination hot- and cold-spots, and determine that the locations of transcriptional regulatory sequences are likely major determinants of conserved recombination breakpoint hot-spot locations. We find that while the locations of recombination breakpoints are not uniformly associated with degrees of nucleotide sequence conservation, they display significant tendencies in multiple coronavirus subgenera to occur in low guanine-cytosine content genome regions, in non-coding regions, at the edges of genes, and at sites within the Spike gene that are predicted to be minimally disruptive of Spike protein folding. While it is apparent that sequence features such as transcriptional regulatory sequences are likely major determinants of where the template-switching events that yield recombination breakpoints most commonly occur, it is evident that selection against misfolded recombinant proteins also strongly impacts observable recombination breakpoint distributions in coronavirus genomes sampled from nature.

Kuwanons, Promising inhibitors against the ACE-2, main protease of SARS-CoV-2 and falcipan-2 using molecular docking (preprint)

In the present scenario, the COVID-19 has affected the nations throughout the world. Till date, neither a vaccine nor a potential medicine is available for the cure from SARS-CoV-2 infection. Main protease of SARS-CoV-2 is responsible for the replication and transcription. Further, this virus binds to the angiotensin converting enzyme-2 (ACE-2) so there is need to find molecule, to avoid the binding of novel virus to ACE-2. It is reported that the molecules binds to falcipan-2 can help in the reduction of infection due to SARS-CoV-2. Therefore, there is a need to find promising candidate against the receptors, spread COVID-19. In the present work, kuwanons are proposed to be promising candidates against the main protease of SARS-CoV-2, ACE-2 and falcipan-2. The interaction between the different kuwanons with different receptors has been studied using the binding energy. Kuwanon M was found to best inhibitor against the main protease of SARS-CoV-2 and ACE-2. Further, the drug-likeness properties of all the 16 kuwanons were studied. Kuwanon-M found to be best inhibitor against the ACE-2 and main protease of SARS-CoV-2 with binding energy of -165.349 and -149.952 kcal/mol respectively while kuwanon-G found out to promising against the falcipan-2 with a binding energy of -149.573 kcal/mol.

Promising inhibitors of main protease of novel corona virus to prevent the spread of COVID-19 using docking and molecular dynamics simulation.

Coronavirus disease-2019 (COVID-19) is a global health emergency and the matter of serious concern, which has been declared a pandemic by WHO. Till date, no potential medicine/ drug is available to cure the infected persons from SARS-CoV-2. This deadly virus is named as novel 2019-nCoV coronavirus and caused coronavirus disease, that is, COVID-19. The first case of SARS-CoV-2 infection in human was confirmed in the Wuhan city of the China. COVID-19 is an infectious disease and spread from man to man as well as surface to man . In the present work, in silico approach was followed to find potential molecule to control this infection. Authors have screened more than one million molecules available in the ZINC database and taken the best two compounds based on binding energy score. These lead molecules were further studied through docking against the main protease of SARS-CoV-2. Then, molecular dynamics simulations of the main protease with and without screened compounds were performed at room temperature to determine the thermodynamic parameters to understand the inhibition. Further, molecular dynamics simulations at different temperatures were performed to understand the efficiency of the inhibition of the main protease in the presence of the screened compounds. Change in energy for the formation of the complexes between the main protease of novel coronavirus and ZINC20601870 as well ZINC00793735 at room temperature was determined on applying MM-GBSA calculations. Docking and molecular dynamics simulations showed their antiviral potential and may inhibit viral replication experimentally. Communicated by Ramaswamy H. Sarma.