Investigating poor respiratory function and high immunological escape in COVID-19 patients may aid in the prevention of additional deaths. The conserved domain search method was used to evaluate the biological roles of specific SARS-COV-2 proteins in this present study. The research findings indicate that the SARS-COV-2 virus contains domains capable of binding porphyrin and synthesizing heme. S and ORF3a can bind to hemoglobin. The S protein possesses hemocyanin-like function since it contains copper-oxygen binding, immunological agglutination, and phenoloxidase domains. ORF3a's Arg134 and E's Cys44 have heme-iron binding sites, respectively. The ORF3a protein has a region that degrades trapped heme into iron and porphyrin. Hemoglobin that has been attacked by ORF3a may preserve the majority of its native structure but with decreased oxygen delivery function. By targeting hemoglobin and destroying heme, the ORF3a protein caused varying degrees of respiratory distress and coagulation symptoms in COVID-19 individuals. ORF3a of Delta and Omicron variants also retained its capacity to target hemoglobin and heme. But the S protein's hemocyanin-like domain transported oxygen to enhance the patient's respiratory condition. Through a large load of hemocyanin-like proteins, the mutant virus achieved effective oxygen transport and alleviated the symptoms of respiratory distress in patients. Simultaneously, the variant S protein's immunological agglutination and phenol oxidase functions were decreased or eliminated, resulting in a decrease in the strength of the immune response and an increase in immune evasion ability, culminating in increased virus transmission.
Based on the reviewers‘ suggestion, major revisions have been made: 1. Rewrite the abstract, background, results and conclusions. 2. Delete the related content of molecular docking and protein docking. 3. To increase the research content of hemocyanin-like activity of S protein. 4. Increase the domain search of ORF3a protein to attack hemoglobin and dissociate heme 5. Delete the first subsection of the discussion.