3.6. Orf6
The orf6 of the SARS-CoV-2 and the BatCoV RaTG13 contain 61 amino acids while it contains 63 amino acids in the SARS-CoV (Table 1). The orf6 proteins of the SARS-CoV-2 and SARS-CoV are characterized by identity percentage of 68.9% and similarity percentage of 88.5%. The identity and similarity percentages of the orf6 of the SARS-CoV-2 and BatCoV RaTG13 were 100% each (Table.2).
The functions of the orf6 include: 1) it participates the formation of replication\transcription to facilitate the viral replication, 2) it increases the number of the virions during the infection, 3) it contributes to the evasion of the virus to the host immune system and 4) it is involved in the formation of the Double Membrane Vesicle (DMV) in the host cells to ensure the virus assembling [40-42].