PE_PGRSs are a large family of Mtb proteins implicated in tuberculosis (TB) pathogenesis that show a modular structure: the N-terminal PE domain, highly homologous to the domain found in tens of others PE proteins and whose structure has been already solved by crystallography; a C-terminal domain that is unique for each protein; the polymorphic glycine-rich domain (PGRS) that varies in length from few tens to more than 1,000 amino acids [1].

1: PGRS domain structures: Doomed to sail the mycomembrane. Berisio R, Delogu G; PLoS Pathog. 2022;18:e1010760. PMID:36048802