Analyzing SARS-CoV-2 Spike Protein Structural Properties: G76V Mutation More Likely to Occur Than V180G

There are two possible mutations in spike protein; G76V and V180G. Which of these two mutations is less likely to occur, from protein structural considerations.

G76V

To determine which of the two mutations, G76V or V180G, is less likely to occur from protein structural considerations, we need to look at the structural properties of the protein and how the mutations would affect them.

The spike protein is a large homotrimeric protein that mediates the entry of SARS-CoV-2 into host cells. It consists of two subunits, S1 and S2, with the receptor-binding domain (RBD) located in the S1 subunit. Both G76 and V180 are located in the receptor-binding motif (RBM) of the RBD.

Glycine (G) is the smallest amino acid and lacks a side chain, which makes it flexible and allows it to occupy tight spaces in protein structures such as turns and loops. Valine (V), on the other hand, is a bulkier amino acid with a branched side chain. When we replace G with V at position 76, the RBM will experience steric clashes due to the increased bulkiness of V, and this could destabilize the RBM and affect its interaction with the host receptor.

In contrast, when we replace V with glycine at position 180, the RBM could become more flexible due to the lack of a bulky side chain, and this could improve its interaction with the host receptor. Therefore, this mutation is less likely to disrupt the RBM and therefore is less likely to affect the protein’s function.

In summary, from protein structural considerations, the G76V mutation is less likely to occur than the V180G mutation due to its potential to cause steric clashes and destabilize the RBM.

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