Chemical shift assignments of a fusion protein comprising the C-terminal-deleted hepatitis B virus X protein BH3-like motif peptide and Bcl-xL

Chronic hepatitis B virus (HBV) infection is a major risk factor for the development of liver diseases including fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). HBV has the multifunctional protein, HBV X protein (HBx, 154 residues), which plays key roles in HBV replication and liver disease development. Interaction of HBx through its BH3-like motif with the anti-apoptotic protein Bcl-x_L leads to HBV replication and induction of apoptosis, resulting in HCC development. Our previous nuclear magnetic resonance (NMR) study revealed that the HBx BH3-like motif peptide (residues 101–136) binds to the common BH3-binding groove of Bcl-x_L. Importantly, a C-terminal-truncated HBx, e.g., residues 1–120 of HBx, is strongly associated with the increased risk of HBV-related HCC development. However, the interaction mode between the C-terminal-truncated HBx and Bcl-x_L remains unclear. To elucidate this interaction mode, the C-terminal-deleted HBx BH3-like motif peptide (residues 101–120) was used as a model peptide in this study. To facilitate the NMR analysis, we prepared a fusion protein of HBx (101–120) and Bcl-x_L connected with five repeats of the glycine-serine dipeptide as a linker. Here, we report the ¹H, ¹³C, and ¹⁵N resonance assignments of the fusion protein. This is the first step for the elucidation of the pathogenesis of liver diseases caused by the interaction between the C-terminal-truncated HBx and Bcl-x_L.