Novel SARS-CoV-2, a bat based virus originated in Wuhan, China that caused a global pandemic in December, 2019 belongs to the Betacorona virus family and contains single stranded genome of ~29Kbp. The host cell invasion of SARS-CoV-2 is facilitated by interaction of C-Terminal Domain (CTD) of Spike (S) protein of virus and host ACE2 receptor in the presence of TMPRSS seine protease secreted by the host cell. In this study the mutation hotspots of S-protein will be identified and the impact of such mutation in the binding affinity will be studied. Additionally, the lead molecule which can bind to the mutated protein also will be identified. Multiple sequence alignment of the spike protein sequence of SARS-CoV-2 shows the number of single amino acid mutation hotspots such as L5F, R214L, R408I, G476S, V483A, H519Q, A520S, T572I, D614G and H655Y. Among these mutations D614G has 57.5% occurrence and G476S, V483A has 7.5% occurrence. The mutated proteins were modelled based on wild type homolog and docked to ACE2 receptor. When the mutated S protein is docked, the ∆G (binding free energy) value is very minimal in mutated protein showed the stability of variants. By the drug repurposing method, 1000 FDA approved drugs were virtually screened for its binding to RBD of S1 domain. Among these drugs Digitoxin, Gliquidone and Zorubicin Hcl binds to spike proteins with higher docking score (lesser than -8.5 Kcal/mol) to both wild type and mutants.

Introduction: Digitalis use in patients with severe heart failure is controversial. We assessed the effects of digitalis therapy on mortality in a large, observational study in recipients of cardiac resynchronization therapy (CRT). Methods: Consecutive patients receiving a CRT-defibrillator in three European tertiary referral centers were enrolled and followed for a median of 28 months. Digitalis use was assessed at the time of CRT implantation. Multivariate Cox-regression model and propensity score matching was used to determine all-cause mortality as primary endpoint. CRT-response (defined as improvement of ≥1 NYHA class), echocardiographic improvement (defined as improvement of LVEF of ≥ 5%), and ICD shocks were assessed as secondary endpoints. Results: The study comprised 552 CRT recipients with standard indications, including 219 patients (40%) treated with digitalis. Compared to patients without digitalis, they had more often atrial fibrillation, poorer LVEF and higher NYHA class (all p ≤ 0.002). Crude analysis of all-cause mortality demonstrated a similar relative risk of death for patients with and without digitalis (HR=1.14; 95% CI 0.88-1.5; p=0.40). After adjustment for independent predictors of mortality, digitalis therapy did not alter the risk for death (adjusted HR=1.04; 95% CI 0.75-1.45; p=0.82). Also, in comparison to 286 propensity score matched patients, mortality was not affected by digitalis intake (propensity adjusted HR=1.11; 95% CI 0.72-1.70; p=0.64). CRT response was predominant in digitalis non-users concerning both improvement of HF symptoms and LVEF (NYHA p<0.01; LVEF p<0.01) while patients on digitalis had more often ventricular tachyarrhythmias requiring ICD shock (p=0.01). Conclusions: Digitalis therapy had no effect on mortality but did negatively affect CRT response and susceptibility to ventricular arrhythmias requiring ICD shock treatment.