Active human hepatitis B viral polymerase expressed in rabbit reticulocytelysate system

Human HBV polymerase has been expressed in reticulocyte lysate system. The expressed protein shows the DNA-dependent DNA polymerase activity. In vitro transcription and translation produces a major protein product with an app arent molecular weight of approximately 100 kD. The HBV DNA polymerase has been characterized biochemically in the condition that the contaminating ce llular DNA polymerases were fairly suppressed by aphidicolin and NEM. The p olymerization reaction is optimal at pH 7.5 and 37 degrees C and the polyme rase requires either MnCl2 or MgCl2, with a preference for MnCl2. The prote in represented an optimal activity in the presence of either 75 mM NaCl or 100 mM KCl, with a higher activity at 75 mM NaCl than 100 mM KCl. Study of the polymerizing activity of the deleted versions of the polymerase protein suggests that the terminal protein is essential for full polymerase functi on and the spacer region may decrease the stability of the P protein.