FAKHRAVAC and BBIBP-CorV vaccine seeds’ binding to angiotensin-converting enzyme 2: A comparative molecular dynamics study

Background: Safety and efficacy of the SARS-CoV-2 inactivated vaccines have been question since the emergence of SARS-CoV-2 variants of concern (VOCs). Using residue fluctuations and statistically comparing RMSF values, have escalated the understanding of the binding dynamics of the viral proteins to their receptors and here in this study, we compared the interaction between inactivated spike proteins (representing FAKHRAVAC and BBIBP-CorV vaccines seed) and the human Angiotensin-Converting Enzyme 2 (hACE2) receptor. Methodology: Through 100 set of accelerated 1 ns comparative molecular dynamics simulations, we analyze the binding dynamics and energy components of these interactions and compared residue backbone fluctuations using entropy and statistics including KL-Divergence and KS-test. Principal Findings: Our results reveal that FAKHRAVAC and Sinopharm exhibit similar binding dynamics and affinity to hACE2. Further examination of residue-wise fluctuations highlights the common behavior of binding key residues and mutation sites between the two vaccines. However, subtle differences in residue fluctuations, especially at critical sites like Q24, Y435, L455, S477, Y505, and F486, raise the possibility of distinct efficacy profiles. Conclusion: These variations may influence vaccine immunogenicity and safety in response to evolving SARS-CoV-2 variants. The study underscores the importance of considering residue-wise fluctuations for understanding vaccine-pathogen interactions and their implications for vaccine design.