The SARS-CoV-2 viral genome contains a positive-strand single-stranded RNA of ~30 kb. Human ACE2 HGNC
protein is the receptor for SARS-CoV-2 virus attachment MESHD
and initiation of infection MESHD
. We propose to use ribonucleases (RNases) as antiviral agents to destroy the viral genome in vitro. In the virions the RNA is protected by viral capsid proteins, membrane proteins and nucleocapsid PROTEIN
proteins. To overcome this protection we set out to construct RNase fusion with human ACE2 HGNC
receptor N-terminal domain (ACE2NTD). We constructed six proteins expressed in E. coli cells: 1) MBP-ACE2NTD, 2) ACE2NTD-GFP, 3) RNase I (6xHis), 4) RNase III (6xHis), 5) RNase I-ACE2NTD (6xHis), and 6) human RNase A HGNC
-ACE2NTD150 (6xHis). We evaluated fusion expression in different E. coli strains, partially purified MBP-ACE2NTD protein from the soluble fraction of bacterial cell lysate, and refolded MBP-ACE2NTD protein from inclusion body. The engineered RNase I-ACE2NTD (6xHis) and hRNase A-ACE2NTD (6xHis) fusions are active in cleaving COVID-19 MESHD
RNA in vitro. The recombinant RNase I (6xHis) and RNase III (6xHis) are active in cleaving RNA and dsRNA in test tube. This study provides a proof-of-concept for construction of fusion protein between human cell receptor and nuclease that may be used to degrade viral nucleic acids in our environment.