N-linked glycosylation of recombinant soluble ectodomain of HKU1 haemagglutinin esterase

Coronaviruses (CoVs) encompass many human pathogens such as HKU-1, OC43, NL63, SARS, MERS and, most recently, nCoV-2019. The spike (S) protein of CoVs has received much attention for its role in host tropism and immunity, but it is becoming increasingly clear that the haemagglutinin esterase (HE) also plays an important role in host adaptation by determining host receptor (sialic acid) specificity. We determined the structure of HKU1 HE by cryo electron microscopy and mapped site-specific N-linked glycosylation by LC-MS/MS of glycopeptides using electron transfer high-energy collision dissociation.