Atomic level fluctuations of connectivity in the structure network of SARS-CoV2-Human ACE2 receptor complex

In this work, we study the non-covalent connectivity of the SARS-CoV2-Human ACE2 receptor complex, as obtained from molecular dynamics simulations, through graph spectral analysis and show the effects of connectivity strength and dynamic stability on the interface region. We also compare these features with those of the less debilitating SARS-CoV1-ACE2 receptor complex. Our analyses of the networks indicate that the Covid-19 complex forms a more robust interface seen at both the bond level as well as in measures of higher order connectivity like cliques, communities, and clusters. We also analyse individual snapshots of the molecular dynamics simulations to show persistent core level connectivity in most of the structures, with exciting differences being exhibited by various key conformations. The utility of such a map is highlighted by locating the mutated residues in the variants of SARS-CoV2, thus providing a tool to rationalize the effect of mutations through rearrangements of the local as well as global environments.