Fig. 2: Cryo-EM density maps of wild-type apo HKU1-A spike protein, its complex with a 9-O-acetylated disialoside and an equivalently ligand-bound W89A mutant.
From: Sialoglycan binding triggers spike opening in a human coronavirus
a, Orthogonal views of the apo HKU1-A spike trimer density map with protomers coloured in grey, orange and blue. b, Density maps of HKU1-A spike protein in complex with the disialoside (in pink). Three distinct classes were observed, with either no, one or three S1B domains in the open conformation. Relative occurrence (%) is indicated. c, Cryo-EM density map of the W89A mutant HKU1-A spike protein obtained in presence of the disialoside.
