Chlamydia Outer Protein (Cop) B from Chlamydia pneumoniae possesses characteristic features of a type III secretion (T3S) translocator protein.

Background: Chlamydia spp. are believed to use a conserved virulence factor called type III secretion (T3S) to facilitate the delivery of effector proteins from the bacterial pathogen to the host cell. Important early effector proteins of the type III secretion system (T3SS) are a class of proteins called the translocators.

Chlamydia pneumoniae CopD translocator protein plays a critical role in type III secretion (T3S) and infection.

Pathogenic Gram-negative bacteria use type III secretion (T3S) to inject effector proteins into the host cell to create appropriate conditions for infection and intracellular replication. Chlamydia spp. are believed to use T3S to infect their host cell, and the translocator proteins are an essential component of this system.