Virulence-related outer membrane protein family

Virulence-related OMP
E. coli OmpX, PDB: 1qj8​.
Identifiers
Symbol	Ail_Lom
Pfam	PF06316
InterPro	IPR000758
PROSITE	PDOC00582
SCOP2	1qj9 / SCOPe / SUPFAM
OPM superfamily	26
OPM protein	1qj8
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary PDB 1ormA:24-171 1q9gA:24-171 1qj8A:24-171

Virulence-related outer membrane proteins, or outer surface proteins (Osp) in some contexts, are expressed in the outer membrane of gram-negative bacteria and are essential to bacterial survival within macrophages and for eukaryotic cell invasion.

This family consists of several bacterial and phage Ail/Lom-like proteins. The Yersinia enterocolitica Ail protein is a known virulence factor. Proteins in this family are predicted to consist of eight transmembrane beta-sheets and four cell surface-exposed loops. It is thought that Ail directly promotes invasion and loop 2 contains an active site, perhaps a receptor-binding domain. The phage protein Lom is expressed during lysogeny, and encode host-cell envelope proteins. Lom is found in the bacterial outer membrane, and is homologous to virulence proteins of two other enterobacterial genera. It has been suggested that lysogeny may generally have a role in bacterial survival in animal hosts, and perhaps in pathogenesis.

Borrelia burgdorferi (responsible for Lyme disease) outer surface proteins play a role in persistence within ticks (OspA, OspB, OspD), mammalian host transmission (OspC, BBA64), host cell adhesion (OspF, BBK32, DbpA, DbpB), and in evasion of the host immune system (VlsE). OspC trigger innate immune system via signaling through TLR1, TLR2 and TLR6 receptors.^[1]