A multiscale model of virus pandemic: Heterogeneous interactive entities in a globally connected world.

This paper is devoted to the multidisciplinary modelling of a pandemic initiated by an aggressive virus, specifically the so-called SARS-CoV-2 Severe Acute Respiratory Syndrome, corona virus n.2. The study is developed within a multiscale framework accounting for the interaction of different spatial scales, from the small scale of the virus itself and cells, to the large scale of individuals and further up to the collective behaviour of populations. An interdisciplinary vision is developed thanks to the contributions of epidemiologists, immunologists and economists as well as those of mathematical modellers. The first part of the contents is devoted to understanding the complex features of the system and to the design of a modelling rationale. The modelling approach is treated in the second part of the paper by showing both how the virus propagates into infected individuals, successfully and not successfully recovered, and also the spatial patterns, which are subsequently studied by kinetic and lattice models. The third part reports the contribution of research in the fields of virology, epidemiology, immune competition, and economy focussed also on social behaviours. Finally, a critical analysis is proposed looking ahead to research perspectives.

Intra- and intermolecular atomic-scale interactions in the receptor binding domain of SARS-CoV-2 spike protein: implication for ACE2 receptor binding.

The COVID-19 pandemic poses a severe threat to human health with unprecedented social and economic disruption. Spike (S) glycoprotein in the SARS-CoV-2 virus is pivotal in understanding the virus anatomy, since it initiates the early contact with the ACE2 receptor in the human cell. The subunit S1 in chain A of S-protein has four structural domains: the receptor binding domain (RBD), the n-terminal domain (NTD) and two subdomains (SD1, SD2). We report details of the intra- and inter-molecular binding mechanism of RBD using density functional theory, including electronic structure, interatomic bonding and partial charge distribution. We identify five strong hydrogen bonds and analyze their roles in binding. This provides a pathway to a quantum-chemical understanding of the interaction between the S-protein and the ACE2 receptor with insights into the function of conserved features in the ACE2 receptor binding domain that could inform vaccine and drug development.