Fig. 8

Two-stage model for the capsid stability enhancement mediated by the C-terminal polyhistidine-peptide. Schematic representation of the interactions of the C-terminal hexahistidine-peptide with the HBcAg-dimer and the proposed two-stage model for capsid stabilizing. (1) The initial three histidine moieties (HHH) of the C-terminus can interact with the conserved amino acid his47 (dark blue) of the HBcAg. This leads to structural adaptations in the capsid assembly domain (green arrows) and dimerization domain (light blue arrows) which in summary strengthen the capsid integrity. (2) The distal histidines (e.g. histidine 4–6) of two C-termini within one dimer can also interact with each other and thereby further enhance the capsid resilience. Inset show a region of the HBcAg-capsid