Crystal structure of measles virus hemagglutinin provides insight into effective vaccines

Area of Science:

• Structural Biology
• Virology
• Immunology

Background:

• Measles remains a significant global cause of childhood illness and death.
• Measles virus (MV) vaccines are highly effective, yet the precise mechanisms of their success are not fully understood.
• Understanding the structure of viral proteins is crucial for developing effective vaccines and antiviral strategies.

Purpose of the Study:

• To determine the crystal structure of the measles virus hemagglutinin (MVH) attachment protein.
• To elucidate the role of N-linked sugars in MVH structure and function.
• To understand how MVH structure contributes to virus-receptor interactions and antibody recognition.

Main Methods:

• X-ray crystallography was employed to determine the three-dimensional structure of the MV hemagglutinin.
• Structural analysis focused on the receptor-binding head domain and its quaternary structure.
• The influence of N-linked glycosylation on protein conformation and accessibility of key residues was investigated.

Main Results:

• The receptor-binding head of MVH adopts a cubic beta-propeller structure and forms a homodimer.
• N-linked sugars obscure large areas of the protein, causing the dimer components to tilt.
• Highly conserved residues at the putative receptor-binding site are exposed and serve as targets for neutralizing antibodies, explaining vaccine efficacy.

Conclusions:

• The structure of MV hemagglutinin reveals a critical role for N-linked sugars in modulating virus-receptor binding and antibody responses.
• These glycosylation patterns contribute to the conserved epitopes targeted by neutralizing antibodies, underpinning the success of measles vaccines.
• Unlike HIV gp120, MVH glycosylation appears to facilitate immune recognition rather than immune evasion.