Abstract
The SARS-CoV-2 spike (S) protein, a primary target for COVID-19 vaccine development, presents two conformations of its Receptor Binding Domain - a receptor-accessible “up” conformation, or a receptor-inaccessible “down” conformation. Here, we report unexpected cold sensitivity of a commonly used S ectodomain construct, and resolution of this cold sensitivity in a “down” state stabilized spike. Our results will impact structural, functional and vaccine studies that use the SARS-CoV-2 S ectodomain.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
1. Abstract has been shortened. 2. Manuscript has been condensed to a Brief Communication format. 3. Figures have been re-organized. 4. New data showing cold sensitivity data on two constructs - hexapro and rS2d-hexapro has been added. 5. Additional negative stain EM data and reconstructions have been added.