Cold sensitivity of the SARS-CoV-2 spike ectodomain

Area of Science:

• Virology
• Structural Biology
• Vaccinology

Background:

• The SARS-CoV-2 spike (S) protein is crucial for viral entry and a key target for COVID-19 vaccines.
• The S protein exists in two main conformations: the receptor-accessible 'up' state and the receptor-inaccessible 'down' state.
• Stabilized S ectodomain constructs are widely used in structural and functional studies.

Purpose of the Study:

• To investigate the temperature sensitivity of the commonly used '2P' stabilized SARS-CoV-2 S ectodomain construct.
• To determine if stabilizing the S protein in the 'down' state affects its cold sensitivity.
• To inform the use of S protein constructs in future research.

Main Methods:

• Characterization of the '2P' SARS-CoV-2 S ectodomain construct under varying temperatures.
• Comparison of the cold sensitivity of the '2P' construct with a 'down' state-stabilized S ectodomain.
• Structural and functional analyses of S protein ectodomain behavior.

Main Results:

• The '2P' stabilized S ectodomain construct exhibits significant sensitivity to cold temperatures.
• This cold sensitivity is abrogated when the S ectodomain is stabilized in the 'down' conformation.
• The 'down' state stabilization confers greater thermal stability to the S ectodomain.

Conclusions:

• The commonly used '2P' S ectodomain construct is not stable at cold temperatures.
• Stabilizing the SARS-CoV-2 S protein in the 'down' state enhances its thermal stability.
• These findings are critical for optimizing structural, functional, and vaccine-related studies involving the SARS-CoV-2 S protein.