Table 1.

Protein structural and free energy change analysis of VP7

Pre-vaccine strain	Post-vaccine strain	Energy change in kcal/mol	Alignment value in RMSD (Å)
RVA/Human-wt/ZAF/SA296GR/84/1984 /G2P[4]	RVA/Human-wt/ZAF/UFS-NGS-NICD18920/2017 /G2P[4]	−0.523	0.018
RVA/Human-wt/ZAF/SA410GR/85/1985 /G2P[4]	RVA/Human-wt/ZAF/UFS-NGS-MRC-DPRU68/2013 /G2P[4]	−1.017	0.018
RVA/Human-wt/ZAF/SA659GR/86/1986 /G2P[4]	RVA/Human-wt/ZAF/UFS-NGS-NICD13522/2014 /G2P[4]	−0.786	0.017
RVA/Human-wt/ZAF/SA405GR/87/1987 /G2P[4]	RVA/Human-wt/ZAF/UFS-NGS-NICD15034/2015 /G2P[4]	−1.592	0.017
RVA/Human-wt/ZAF/SA514GR/87/1987 /G2P[4]	RVA/Human-wt/ZAF/UFS-NGS-NICD12041/2013 /G2P[4]	−0.528	0.019

The table includes five G2 strains that circulated in South Africa from 1984−1987 and clustered in lineage I alongside the prototype DS-1-like strain. Five post-vaccine G2 strains were randomly selected for the protein structural and free energy change analyses. Protein stability was predicted by estimating the energy change, expressed in kcal mol⁻¹, between a pre-vaccine strain and post-vaccine strain. The energy change o ±0.5 was regarded significant for stabilizing or destabilizing effect. A positive (+) value indicates destabilizing effect while a negative (−) value indicates stabilizing effect. The impact of mutation on the structural conformation of the protein was assessed by superposing a pre-vaccine strain with a post-vaccine strain and the RMSD (Root Mean Square Deviation) alignment value expressed in Angstroms (Å). An RMSD value of zero indicates absolute structural alignment