Effect of SARS-CoV-2 B.1.1.7 mutations on spike protein structure and function

Area of Science:

• Virology
• Structural Biology
• Immunology

Background:

• The SARS-CoV-2 B.1.1.7 variant, originating in the UK, possesses spike protein mutations.
• These mutations may improve binding to human ACE2 receptors and facilitate immune evasion.
• Understanding the structural basis of these changes is crucial for developing effective countermeasures.

Purpose of the Study:

• To determine the cryo-electron microscopy (cryo-EM) structures of the B.1.1.7 spike protein.
• To investigate the impact of B.1.1.7 mutations on ACE2 receptor binding.
• To assess the efficacy of neutralizing antibodies against the B.1.1.7 variant.

Main Methods:

• Cryo-electron microscopy (cryo-EM) to resolve spike protein structures.
• Biochemical assays to study receptor binding interactions.
• Pseudovirus neutralization assays to evaluate antibody efficacy.

Main Results:

• The B.1.1.7 spike protein exhibits altered conformations with increased ACE2 receptor engagement.
• The A570D mutation acts as a molecular switch influencing RBD dynamics.
• The N501Y mutation enhances ACE2 binding and reduces antibody recognition.
• A two-neutralizing antibody cocktail effectively neutralizes SARS-CoV-2 pseudoviruses, including B.1.1.7.

Conclusions:

• The structural insights into B.1.1.7 spike protein provide a molecular basis for its enhanced binding and immune evasion.
• The identified mutations highlight key targets for therapeutic intervention.
• The tested antibody cocktail demonstrates broad neutralization potential against SARS-CoV-2 variants.