NMR characterization of the interaction between Bcl-xL and the BH3-like motif of hepatitis B virus X protein

Biochem Biophys Res Commun. 2019 Oct 20;518(3):445-450. doi: 10.1016/j.bbrc.2019.08.036. Epub 2019 Aug 19.

Abstract

Hepatitis B virus X protein (HBx) possesses a BH3-like motif that directly interacts with the anti-apoptotic proteins, Bcl-2 and Bcl-xL. Here we report the interaction between the HBx BH3-like motif and Bcl-xL, as revealed by nuclear magnetic resonance spectroscopy. Our results showed that this motif binds to the common BH3-binding hydrophobic groove on the surface of Bcl-xL, with a binding affinity of 89 μM. Furthermore, we examined the role of the tryptophan residue (Trp120) in this motif in Bcl-xL binding using three mutants. The W120A mutant showed weaker binding affinity (294 μM) to Bcl-xL, whereas the W120L and W120F mutants exhibited almost equivalent binding affinity to the wild-type. These results indicate that the bulky hydrophobic residues are important for Bcl-xL binding. The findings will be helpful in understanding the apoptosis networks between viral proteins and host factors.

Keywords: BH3-like motif; Bcl-x(L); HBx; NMR.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Binding Sites
  • Hepatitis B / metabolism*
  • Hepatitis B virus / metabolism*
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Models, Molecular
  • Nuclear Magnetic Resonance, Biomolecular
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protein Interaction Maps
  • Trans-Activators / chemistry
  • Trans-Activators / metabolism*
  • Viral Regulatory and Accessory Proteins
  • bcl-X Protein / chemistry
  • bcl-X Protein / metabolism*

Substances

  • BCL2L1 protein, human
  • Trans-Activators
  • Viral Regulatory and Accessory Proteins
  • bcl-X Protein
  • hepatitis B virus X protein