Structure-based design of prefusion-stabilized SARS-CoV-2 spikes
Ching‐Lin Hsieh, Jory A. Goldsmith, Jeffrey M. Schaub, Andrea M. DiVenere, Hung‐Che Kuo, Kamyab Javanmardi, Kevin Le, Daniel Wrapp, Alison G. Lee, Yutong Liu, Chia‐Wei Chou, Patrick O. Byrne, Christy K. Hjorth, Nicole V. Johnson, John Ludes-Meyers, Annalee W. Nguyen, Juyeon Park, Nianshuang Wang, Dzifa Amengor, Jason J. Lavinder, Gregory C. Ippolito, Jennifer A. Maynard, Ilya J. Finkelstein, Jason S. McLellan
Abstract
The coronavirus disease 2019 (COVID-19) pandemic has led to accelerated efforts to develop therapeutics and vaccines. A key target of these efforts is the spike (S) protein, which is metastable and difficult to produce recombinantly. We characterized 100 structure-guided spike designs and identified 26 individual substitutions that increased protein yields and stability. Testing combinations of beneficial substitutions resulted in the identification of HexaPro, a variant with six beneficial proline substitutions exhibiting higher expression than its parental construct (by a factor of 10) as well as the ability to withstand heat stress, storage at room temperature, and three freeze-thaw cycles. A cryo-electron microscopy structure of HexaPro at a resolution of 3.2 angstroms confirmed that it retains the prefusion spike conformation. High-yield production of a stabilized prefusion spike protein will accelerate the development of vaccines and serological diagnostics for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).