Fig. 5. Signal sequence-mediated transport of S into the lumen of the ER.

a Schematic of the process using the authentic viral signal peptide only (as in the vaccines of BionTech-Pfizer, Moderna, Janssen-Johnson&Johnson and Gamaleya Institute). In the CanSino vaccine, the signal peptide of S is replaced by that of human tPA (https://patents.google.com/patent/CN111218459B/en). b Schematic of the process using an additional N-terminal leader sequence (signal peptide and propeptide of tPA), as used in the vaccine of Oxford-Astra Zeneca, based on reference. ⁸⁰). SP—signal peptide; SRP—signal recognition particle; tPA—tissue plasminogen activator; ER—endoplasmic reticulum; C-ter—C terminus; N-ter—N terminus.