Missense mutations in spike protein of SARS-CoV-2 delta variant contribute to the alteration in viral structure and interaction with hACE2 receptor.

INTRODUCTION: Many of the global pandemics threaten human existence over the decades among which coronavirus disease (COVID-19) is the newest exposure circulating worldwide. The RNA encoded severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus is referred as the pivotal agent of this deadly disease that induces respiratory tract infection by interacting host ACE2 receptor with its spike glycoprotein. Rapidly evolving nature of this virus modified into new variants helps in perpetrating immune escape and protection against host defense mechanism. Consequently, a new isolate, delta variant originated from India is spreading perilously at a higher infection rate. METHODS: In this study, we focused to understand the conformational and functional significance of the missense mutations found in the spike glycoprotein of SARS-CoV-2 delta variant performing different computational analysis. RESULTS: From physiochemical analysis, we found that the acidic isoelectric point of the virus elevated to basic pH level due to the mutations. The targeted mutations were also found to change the interactive bonding pattern and conformational stability analyzed by the molecular dynamic's simulation. The molecular docking study also revealed that L452R and T478K mutations found in the RBD domain of delta variant spike protein contributed to alter interaction with the host ACE2 receptor. CONCLUSIONS: Overall, this study provided insightful evidence to understand the morphological and attributive impact of the mutations on SARS-CoV-2 delta variant.

Evaluation of the susceptibility and fatality of lung cancer patients towards the COVID-19 infection: A systemic approach through analyzing the ACE2, CXCL10 and their co-expressed genes.

Coronavirus disease-2019 (COVID-19) is a recent world pandemic disease that is caused by a newly discovered strain of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS- CoV-2). Patients with comorbidities are most vulnerable to this disease. Therefore, cancer patients are reported to be more susceptible to COVID-19 infection, particularly lung cancer patients. To evaluate the probable reasons behind the excessive susceptibility and fatality of lung cancer patients to COVID-19 infection, we targeted the two most crucial agents, Angiotensin-converting enzyme 2 (ACE2) and C-X-C motif 10 (CXCL10). ACE2 is a receptor protein that plays a vital role in the entry of SARS-CoV-2 into the host cell and CXCL10 is a cytokine mainly responsible for the lung cell damage involving in a cytokine storm. By using the UALCAN and GEPIA2 databases, we observed that ACE2 and CXCL10 are mostly overexpressed in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). We then identified the functional significance of ACE2 and CXCL10 in lung cancer development by determining the genetic alteration frequency in their amino acid sequences using the cBioPortal web portal. Lastly, we did the pathological assessment of targeted genes using the PANTHER database. Here, we found that ACE2 and CXCL10 along with their commonly co-expressed genes are involved respectively in the binding activity and immune responses in case of lung cancer and COVID-19 infection. Finally, based on this systemic analysis, we concluded that ACE2 and CXCL10 are two possible biomarkers responsible for the higher susceptibility and fatality of lung cancer patients towards the COVID-19.

A next generation sequencing (NGS) analysis to reveal genomic and proteomic mutation landscapes of SARS-CoV-2 in South Asia.

Counts for SARS-CoV-2 associated infections and fatalities are on the rise globally even in regions which contained the spread momentarily. The pattern of infections has been found to be controlled by the distinctive selection pressures exerted by fluctuating environmental nature and hosts. A total of 410 whole-genome sequences submitted by the South Asian countries were retrieved from the GISAID database and analyzed to assess the impact and pattern of mutations in this region. Most common and frequent mutations in the South Asian countries are 241C > T, 3037C > T, 14408C > T, and 23403A > G and about 85% SNPs are localized in ORF1ab, spike protein, and nucleocapsid. Among the identified mutations, the proportion of missense type (54.17%) was highest, followed by the synonymous (41.66%) and the non-coding types (4.17%). While analyzing transmission source in terms of geolocation, the largest clustered group from the South Asian countries was based on the G-clade (D614G) (81.7%; 335/410 samples), tracing the inception and transmission of SARS-CoV-2 infections in the South Asian countries from European regions. Phylogenetic analysis also revealed that the South Asian strains are highly related to the South American and European strains. We found that G-clade mutations are more prevalent (96.19%) in the samples of Bangladesh which were also prevalent in the European isolates. Surprisingly, one missense mutation (1163A > T) in ORF1ab gene became dominant only in Bangladesh (78.8%), which led to debates regarding effects on the pathogenicity and transmissibility of the virus. Overall, the findings of this study highlight the frequently mutated SARS-CoV-2 variants among the COVID-19 patients in the South Asian countries which might ease containment of the disease in this region through investigating the virulence reducing factors as the identified mutations are strongly correlated with low infection and mortality rate.