THE PHOSPHORYLATION SITE T478 AND SURROUNDING AMINO ACIDS ARE NOT PRESENT IN THE SPIKE PROTEIN OF THE BAT RELATIVE OF SARS-COV-2, YUNNAN_RATG13: COMPARATIVE STRUCTURE MODEL ANALYSIS AND STUDY OF STABILITY AND BINDING TO ACE2 DEBUNKS THE IDEA THAT SARS-COV-2 IS THE RESULT OF LABORATORY MANIPULATION.

The origin of SARS-COV-2 has generated much controversy and debate. Several so-called experts and pundits have claimed that the Bat relative of SARS-COV-2, Yunnan_RaTG13 has undergone laboratory manipulation to generate SARS-COV-2. Examination of the sequence of the Spike protein (SPp) of Bat Yunnan_RaTG13 shows that the phosphorylation site T478 and surrounding amino acids that are present in SPp of SARS-COV-2 are missing in SPp of Yunnan_RaTG13. Here, through structure model analysis and thermodynamic calculation, it is shown that the binding efficiency of SPp of Yunnan_RaTG13-ACE2 complex is significantly distinct from SPp of SARS-COV-2-ACE2 complex. It is shown that phospho-T478 reduces the stability of SPp of SARS-COV-2-ACE2 complex and the binding efficiency of SPp of SARS-COV-2 to ACE2. Engineering T478 and surrounding amino acids into SARS-COV-2 would be futile as phosphorylation of T478 resulted in a SPp of SARS-COV-2 that binds ACE2 with lower binding efficiency and a SPp of SARS-COV-2-ACE2 complex that is significantly less stable. The above results clearly debunk the ides that SARS-COV-2 is derived from Bat Yunnan_RaTG13 through laboratory manipulation at the Wuhan Institute of Virology. The suggestion that SARS-COV-2 originated as a result of laboratory experimental manipulation of Bat Yunnan_RaTG13 at the Wuhan Institute of Virology is debunked because prior to the current work, no-one noticed that the phosphorylation site T478 and surrounding amino acids are missing in Bat Yunnan_RaTG13 and the function of phospho-T478 and surrounding amino acids was unknown. One does not engineer a virus that would make it less stable and less efficient at infecting its host cells. The present work shows that phosphorylation of T478 of SPp of SARS-COV-2 by cellular protein kinase such as GSK-3 and Cdk1 will be accompanied by lower and not higher rate of infection. The present work also shows that Pangolin Guangdong MP 789 is most probably an ancestor of SARS-COV-2 and Pangolin is most probably an intermediate carrier of SARS-COV-2 because the phosphorylation sites S477 and T478 and surrounding amino acids that are present within the ACE2 receptor binding domain of the SPp of SARS-COV-2 is also present in Pangolin Guangdong MP 789. It is not clear why research work on Pangolin coronaviruses and Pangolin as intermediate animal carrier of SARS-COV-2 has not received the attention that it deserves