Regulatory Interactions between APOBEC3B N- and C-Terminal Domains

Area of Science:

• Biochemistry
• Structural Biology
• Cancer Research

Background:

• APOBEC3B (A3B) contributes to DNA mutations driving tumor evolution.
• While individual domains of A3B are structurally characterized, the full-length protein's (fl-A3B) structure and dynamics remain unclear.
• The C-terminal domain (A3Bctd) is often depicted in a closed conformation.

Purpose of the Study:

• To elucidate the structural dynamics of full-length APOBEC3B (fl-A3B).
• To investigate the mechanism of fl-A3B active site opening.
• To identify potential druggable sites on fl-A3B for cancer therapy.

Main Methods:

• Integrative structural biology for fl-A3B modeling.
• Conventional and Gaussian accelerated molecular dynamics (MD) simulations.
• Weighted ensemble methods to study active site dynamics.

Main Results:

• A top model of fl-A3B was generated and analyzed for dynamics.
• Comparison of A3Bctd and fl-A3B dynamics revealed distinct behaviors.
• NTD-CTD interface interactions were found to increase fl-A3B active site opening frequency.

Conclusions:

• The study provides insights into the dynamic mechanisms of fl-A3B.
• Observed active and allosteric sites suggest potential for therapeutic targeting.
• Understanding A3B dynamics may open new avenues for cancer treatment.