Putative Hydrophobic Gate in the 5-Fold Axis of TrV Viral Capsid

JUAN FRANCISCO VISO; LOPEZ-MARIJUAN ; FERNANDO ZAMARREÑO; MARÍA J. AMUNDARAIN; DIEGO M.A. GUÉRIN; MARCELO D. COSTABEL

Bilbao

Otro; BioFiViNet III - Physical Virology: From Structure to Evolution.; 2015

Red Española Interdisciplinar de Biofísica de los Virus (Biofivinet).

In this work we study the capsid of the Triatoma Virus (TrV, Dicistroviridae: Cripavirus), an insectvirus whose capsid has icosahedral symmetry. We focused our attention to the 5-fold symmetryaxis in which exists a cavity or 'pore' that radially traverses the capsid. Although this cavity has anarrowing at its middle part, fluctuations in the protein could allow the passage of solventmolecules and/or ions. The TrV crystallographic structure shows that the cavity is partially filledwith solvent molecules, but it also displays some unexplained density bulges along the 5-fold axis(Figure 1). Using Molecular Dynamics simulations (MD) and in the absence of ions within thecavity, we observed that the central portion of the pore remains dehydrated. On the contrary,MD calculations showed that when a magnesium ion is located in a position close to glutamineresidues, the ion remains stable along the simulation period, and the pore becomes fullyhydrated.