Biological and Medicinal Chemistry

COVID-19: CRISPR/Cas-like System of nsp3 Promotes the Mutant Recombination and Drug Resistance



Patients with novel coronavirus pneumonia usually suffer from bacterial and fungal infections, and the drug resistance problem caused by the pandemic is becoming more and more serious. Simultaneously, the SARS-COV-2 virus has a rapid mutation phenomenon, and somegene coding regions by mutation and recombination may be related to the drug resistance of the virus. Therefore, studying the relationship between the co-infection of bacteria and fungi and the evolution of SARS-COV-2 has important guiding significance for preventing a pandemic. We found that the SARS-COV-2 virus's nsp3 protein had a CRISPR/Cas 9 (II-B)-like function by searching for conserved domains. The system could target and edit the negative-strand RNA of SARS-COV-2. We speculated that the crRNA (CRISPR RNA) produced by the CRISPR/Cas system of Pseudomonas aeruginosa carried the genetic information of the conserved domains of bacteriophages and Pseudomonas, including drug resistance. After the phage lysed the Pseudomonas, the crRNA was released and attached to the fungal spores, and then invaded the patient's cells along with the spores or hyphae. nsp3 synthesized and assembled 4Fe-4S, iron-containing molecules bound to the cas4 domain, in the mitochondria of phagocytes. The iron came from hemoglobin attacked by the SARS-COV-2 virus protein. The nsp3 protein bound the crRNA in the phagocytic cytoplasm. It targeted the negative-strand RNA of SARS-COV-2, inserting conserved domain gene fragments into the negative-strand RNA through editing and splicing. Since the Cas protein had no codon checking function, the cutting and splicing would destroy the protein-coding information in the original RNA coding region, causing mutation and recombination of the SARS-COV-2 virus genome. If crRNA carried the drug resistance gene fragments of bacteria or phage, SARS-COV-2 would have similar drug resistance. Because of the growing problem of drug resistance in COVID-19 patients, we should pay attention to preventing fungi and bacteria co-infection. Avoid the CRISPR/Cas-like system of the novel coronavirus to cause rapid mutation and recombination and increased the drug resistance problem of SARS-COV-2.


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