Fig. 6.

The ACE2 and TMPRSS2 host factors. (A) ACE2 in complex with RBD of the SARS-CoV-2 S protein (PDB ID 6m0j). The ACE2 structure is displayed in grey surface whereas its S protein interacting region and its catalytic site are colored green and purple, respectively. ACE2 bound SARS-CoV-2 S protein RBD is shown as a cyan cartoon. (B) Cartoon presentation of the ACE2 RBD interface with interacting residues of both proteins shown as sticks. (C) Cartoon presentation of the TMPRSS2 homology modeled structure. The catalytic triad is shown as cyan sticks and the two domains of the outer membrane region of TMPRSS2 are labeled. (D) Chemical structures of the two known inhibitors of TMPRSS2.