Single Amino Acid Variant (SAV) Percentage and Monomer Modeling of Spike Protein of SARS-CoV-2 in Jordan (preprint)

ABSTRACT

Spike protein is the surface glycoprotein of the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) necessary for the entry of the virus via the transmembrane receptors of the human endothelial cells of the respiratoty system for the virus to be engulfed causing COVID-19 disease after priming by type II transmembrane protease TMPRSS2 and then binding with the angiotensin-converting enzyme 2 (ACE2). Therefore, mutations and amino acid variants analysis are essential in understanding the mechanism of binding of spike protein with its receptor to have an insights on possibilities to design a peptide or nucleotide-based vaccine for COVID-19. Here, we employed Iterative Threading Assembly Refinement (I-TASSER) and Multiple Alignment using Fast Fourier Transform (MAFFT) to predict the three-dimensional monomer structure of spike protein of SARS-CoV-2 and to analyze the amino acid variants for protein sequences from GISAID database for samples collected from Jordan in a try to find an explanation for the low confirmed number of COVID-19 in Jordan. Our Protein Homology/analogY Recognition Engine V 2.0 (Phyre2) findings showed four single amino acid variants (SAV) found in 20 samples of SARS-CoV-2. What is equal to 5% of samples showed tyrosine deletion at Y144 located in the SARS-CoV-like_Spike_S1_NTD (N terminal domain), 62% showed aspartate substitution to glycine at D614G located in the SARS-CoV-2_Spike_S1_RBD (spike recognition binding site), 5% showed aspartate substitution to tyrosine at D1139Y and 5% showed glycine substitution to serine at G1167S both located in the Corona_S2 domain. The findings have shown lower mutational sensitivity in all variants that might not affect the function of spike glycoprotein except for D614G, which has the highest mutational sensitivity score (5 out of 9) indicating a higher likelihood to affect the function of the spike protein. This might suggest, in general, a reduced transmitability of SARS-CoV-2 in Jordan.