SARS-CoV-2(6) increasingly(4) drug(4) free energy(4) human ACE2(4) RBD(4) Spike proteins(4) de novo(4) conditions(4) drugs(4) Spike protein(4) Free energy calculations(4) validation(4) disease(4) drug candidate(4) applied(4) spike(4) docking(4) Receptor binding domain(4) repurposing therapeutics(4) receptor(4) similarity(4) approach(4) COVID-19(4) experiments(4) repurposing(4) hACE2(4) de Novo drug design(4) Viral(4) binding(4)