FIG. 1.
Overview of the SARS-CoV genome organization and proteins (20). The positions of coronavirus group-specific genetic and structural markers are indicated. SARS-CoV has the markers of group 2 coronaviruses. In the N-terminal part of the S protein, only Cys residues are distributed in a group-specific fashion (5) (dashed line). SUD, SARS-CoV-unique domain; PL2pro, group 2 papain-like protease 2; TM2, transmembrane domain 2; 3CLpro, chymotrypsin-like protease related to 3Cpro of picornaviruses.