... protein, with only two glycosylationsites can be independently folded and secreted in a solu-ble form, and can bind ACE2.The potential glycosylation sites in RBD fragments are functional and glycosylation ... and then incu-bated with the secondary antibody conjugated with HRP for 1 hour, washed four times, each time for 15 min, and then developed using the ECL reagent (Pierce, Rockford,IL).Cell binding ... residues 327 and 490 [8]. The S317–518 and S319–518 fragments were secreted in the culture superna-tant (Fig 1A), and bound to ACE2-expressing cells (Fig 1B) and purified ACE2 (Table 1 and data...