In Silico Screening, ADMET Analysis, MD Simulations, and MM/PBSA Binding
Free Energy Identify New Inhibitor Molecules for Viropiron E.
Abstract
While advances in vaccine technology allowed the rapid production and
approval of COVID-19 vaccines, the availability of antivirals has relied
mainly on drug repurposing. Most of the proposed antivirals aim to
inhibit viral entry or regulate the severity of the coronavirus
infection. Of the SARS-CoV-2 three structural proteins (membrane,
envelope, and nucleocapsid) that play an essential role in the assembly
and formation of infectious virion particles, the envelope protein (E
protein) is the least studied in terms of finding inhibitors of its
function using repurposed drugs. E protein can homo-oligomerize to form
a pentamer that functions as a cation-selective ion channel. This study
aimed to find potential antiviral molecules targeting SARS-CoV-2
viroporin E. To achieve this, we applied virtual screening methods to
the ASINEX antiviral library that contains 6827 compounds. Eight
promising inhibitors were identified. The docking process was conducted
on a structure of the SARS-CoV-2 viroporin E (2-E) taken from the
NMR-resolved structure published by Cao Y. et al. [5], showing that
these compounds could accommodate within the 2-E channel through
aliphatic, aromatic, and polar interactions with the amino acid residues
Val18, Leu20, Phe16, Phe19, and Thr23 of helices B, D, and E of the
pentamer. All these compounds showed excellent ADMET properties like
absorption, metabolism, minimal toxicity, and bioavailability. They
remained stabilized at the binding site of viroporin E during the MD
simulation and confirmed by MMPBSA results. The identified lead
compounds are proposed as effective inhibitors of the 2-E by inhibiting
the envelope formation and virion assembly.