Author
Abstract
Occult hepatitis B infection (OHB) is defined as infection with detectable HBV DNA and undetectable surface antigen (HBsAg) in patients' blood. It is believed that detection of hepatitis B virus by host in “a” region of surface antigen (HBsAg) is performed. However, there have never been successful attempts to provide evidence for this hypothesis, partly because the 3D structure of HBsAg molecule has not been determined. Tertiary structure prediction of HBsAg solely from its primary amino acid sequence may reveal the structural changes of the mutant proteins. We carried out this study to analyze the predicted HBsAg conformation changes of OBH variant and wild isolated from Iranian patient blood. We extracted HBsAg sequences (OBH and wilde) of Iranian from Gen Bank. Tertiary structures of the wild & occult HBsAg were predicted using “ab initio” modeling and I-TASSER method. Then visualized using deep View/Siwss-pdb Viewer. Dipole moments of 3D structures were determined by chimera software. Wild & occult HBsAg sequences were analyzed in CLC Main Workbench to prediction antigenic index of each sequence. Our results showed the single amino acid substitutions in OBH, may alter structural properties of variant HBsAg, which can be shown by both its antigenic index and dipole moment of predicted 3D conformation. This survey suggested that the moreover “a" region mutations, other mutations can be change structure of HBsAg. It suggested to detection and vaccine design should be pay attention to three-dimensional structure of HbsAg.
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