Molecular Basis of Differential Stability and Temperature Sensitivity of ZIKA versus Dengue Virus Protein Shells

Abstract

Rapid spread of ZIKA virus (ZIKV) and its association with severe birth defects have raised worldwide concern. Recent studies have shown that ZIKV retains its infectivity and remains structurally stable at temperatures up to 40 °C, unlike dengue and other flaviviruses. In spite of recent cryo-EM structures that showed similar architecture of ZIKA and dengue virus (DENV) E protein shells, little is known that makes ZIKV so temperature insensitive. Here, we attempt to unravel the molecular basis of greater thermal stability of ZIKV over DENV2 by executing atomistic molecular dynamics (MD) simulations on the viral E protein shells at 37 °C. Our results suggest that ZIKA E protein shell retains its structural integrity through stronger inter-raft communications facilitated by a series of electrostatic and H-bonding interactions among multiple inter-raft residues. In comparison, the DENV2 E protein shell surface was loosly packed that exhibited holes at all 3-fold vertices, in close agreement with another EM structure solved at 37 °C. The residue-level information obtained from our study could pave way for designing small molecule inhibitors and specific antibodies to inhibit ZIKV E protein assembly and membrane fusion.