Assembly-active and -inactive forms of HBV capsid protein provide distinctly different binding sites for capsid assembly modulators.

Distinct CAM binding site conformations are observed between assembly-active Cp150 capsids and assembly-inactive Cp149-Y132A structures of HBV core protein.

• Why it matters: Understanding how CAMs interact with different HBV core protein forms is crucial for designing effective antivirals, as current knowledge of binding site variability is limited.
• What they did: The study compared structures of CAM-bound Cp150 and Cp149-Y132A, revealing that CAM sites in capsids undergo an induced fit, while in Cp149-Y132A crystals, CAM sites show minimal structural change, with residue interactions remaining nearly constant.
• The result: These findings highlight structural differences in CAM binding that can inform future antiviral design efforts targeting HBV capsid assembly.