Abstract
BackgroundWith the start of the Coronavirus disease19 (COVID19) pandemic, the Coronavirus has mutated constantly. Recently a new variant called Delta plus has been reported in few countries, including South Africa, Brazil and India. The Delta plus variant contains an additional mutation called K417N on the coronavirus spike. The present study aims to determine the virulence and transmissibility of the Delta plus variant and to check the efficiency of different antibodies on its neutralization.Materials and MethodsDifferent computational tools such as PROVEAN, an online tool, HOPE server, simulation using CABS Flex, Clus pro, an online docking tool, were used to predict the structure and function of Delta plus variant by performing a comparative study with wild type protein. Also, to find an effective antibody against Delta plus variant, antigen-antibody docking studies were conducted through Clus pro server. Furthermore, we performed a 2D interaction diagram analysis to find the amino acid residue's interaction against antibodies.Results PROVEAN and HOPE showed the mutation (K417N) in the S-glycoprotein of Delta plus as NEUTRAL mutation. This mutation causes the loss of cysteine bonds leading to the destabilization of the 3D structure of spike protein. Furthermore, the RMSF plot emphasizing the 17th amino acid position of wild and Delta plus mutant revealed the high fluctuation of mutant protein structure compared to the wild protein structure. Further, a comparative docking study against hACE2 shows higher binding energy of wild-type RBD (-751.7 kcal/mol) than mutant RBD (-750.1 kcal/mol). Moreover, antigen-antibody docking study revealed higher affinity of BD-23 Fab antibodies with greater interaction energy ( -997 kcal/mol) compared to other antibodies and thus may prove to be a promising therapeutic against Delta plus variant.ConclusionDelta plus variant is less stable, has a lower binding affinity to hACE2 and has less virulence than wild type. However, the BD-23 Fab antibody has shown a more significant association for this variant and can be used in its treatment.