This domain is found in Immunodominant antigen Pgp3, a virulence protein from Chlamydia trachomatis involved in stimulating host immune responses and thought to be required for growth within mammalian cells. Pgp3 consists of globular N- and C-terminal domains (Pfam:PF05475 is the latter) connected by a triple-helical coiled coil (THCC). The N-terminal domain (this entry), which includes several structural motifs typically found in trimeric viral proteins, folds into a fairly flat surface [1-3].

1: Structure of the Chlamydia trachomatis immunodominant antigen Pgp3. Galaleldeen A, Taylor AB, Chen D, Schuermann JP, Holloway SP, Hou S, Gong S, Zhong G, Hart PJ; J Biol Chem. 2013;288:22068-22079. PMID:23703617

2: Chlamydia protein Pgp3 studied at high resolution in a new crystal form. Khurshid S, Govada L, Wills G, McClure MO, Helliwell JR, Chayen NE; IUCrJ. 2018;5:439-448. PMID:30002845

3: The structure of a plasmid of Chlamydia trachomatis believed to be required for growth within mammalian cells. Comanducci M, Ricci S, Ratti G; Mol Microbiol 1988;2:531-538. PMID:2845228