Question

Variants of SARS-CoV-2 have emerged that have differences in the spike protein. These differences can affect immunity and viral function.

With the knowledge of the genetic code, transcription and translation, what happens to the genes that affect the protein that is produced.

Answer 1

The coronavirus spike protein mediates entry of coronavirus into host cells is a multifunctional molecular machine and a large type I transmembrane protein. , this protein is highly glycosylated containing 21 to 35 N-glycosylation sites. Spike proteins act like trimers on the virion surface forming a distinctive "corona", or crown-like appearance. It has a subunit called S1 which binds to a receptor of the host cell surface ans subunit S2 leads to fusing of viral and host membranes . S1 domains of different coronaviruses helps in recognizing variety of host receptors, leading to viral attachment. The spike protein has two conformations, prefusion and postfusion.

There were studies made to understand the genomic structure and the variations of the SARS-CoV-2. The study included analysis of 95 SARS-CoV-2 complete genome sequences which are available in various gene libraries worldwide like the GenBank, National Microbiology Data Center (NMDC), NGDC Genome Warehouse. The analysis of genomic signature shows a strong association between sample collection time, sample location, accumulation of genetic diversity etc. In the studies made of this virus arouns 116 mutations were found, three most common mutations being 8782C>T in ORF1ab gene, 28144T>C in ORF8 gene and 29095C>T in the N gene. While genomic coding, during the process of transcription the information stored in the DNA is transferred to a m RNA (messenger ribonucleic acid) , this mRNA contains the information from these various codes of DNA along with the mutations, comprising information for making protein

Translation occurs in a much general way for getting a protein from a gene, this takes place in the cytoplasm. The mRNA interacts with a specialized complex called a ribosome, ribosomes reads sequence of mRNA bases. A sequence with three base is called a codon, which codes for one particular amino acid.Transfer RNA (tRNA) assembles the protein, and this assembly continues until the ribosome encounters a “stop” codon. These mutations along with many other genetic mutations resulted in the severity and spread of the SARS-CoV-2. The mutations are increasing coding for variety of proteins including spike proteins and thus infection and disease symptoms are also varying.