The focus of this study was the computational analysis of hepatitis B virus (HBV) genotype D subgenotype D1 in Pakistan, China, and India. In total, 54 complete genome sequences of HBV genotype D subgenotype D1 were downloaded from National Center for Biotechnology Information (NCBI). Of these, 6 complete genome sequences were from Pakistan, 14 were from China, and 34 were from India. Sequence alignment showed less than 4% divergence in these sequences. C and X genes showed divergence of less than 3%. Comparison over the S gene showed more than 97% similarity among the nucleotide sequences of genotype D subgenotype D1. The identity and similarity matrix of 54 nucleotide sequences of HBV genotype D subgenotype D1 from Pakistan, China, and India revealed more than 93% identity and 93% similarity. Phylogenetic analysis highlighted that complete genome isolates of HBV circulating in Pakistan had the closest evolutionary relationship with its neighboring countries China and India. China’s () and Pakistan’s () isolates shared the same ancestor. Gene structure analysis showed that “P” gene exons were the longest, about three-fourth of the genome size, whereas gene “S” had the second longest coding regions with 2 exons and 1 intron. However, “C” and “X” genes had 1 smallest exon. X proteins hadproven role in spreading of the HBV infection diseases. For HBx analysis, 1 Xprotein sequence of HBV genotype D subgenotype D1 belonging to each country wasobtained. Homology models of the 3 X proteins generated using SWISS-MODELrevealed GMQE (Global Model Quality Estimation) = 0.1. Global and local qualityestimate scores including Z-scores for Qualitative Model EnergyAnalysis (QMEAN) C-beta, all-atom, solvation, and torsion energy scores weresimilar indicating good quality, accuracy, and reliability of the predictedmodels. Three-dimensional (3D) visualization showed similar structures andRamachandran plots showed a high percentage of protein residues into thefavorable region for X protein models.
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