A mere 3 months after identification of SARS-CoV-2 as the etiologic agent of COVID-19, structures of the complex between ACE2 and the receptor binding domain (RBD) (Wang et al., 2020; Lan et al., 2020; Yan et al., 2020) and of the ectodomain of trimeric Spike (Walls et al., 2020; Wrapp et al., 2020) were already solved by X-ray crystallography or cryo-electron microscopy. Here, ACE2 is linked to COVID-19.