Fig 2.

Schematic of the type IV secretion system in N. meningitidis. In gonococci, the partitioning protein homologs ParA and ParB may bind DNA and bring it to the T4SS apparatus. The relaxase, TraI, nicks DNA and it is unwound by a helicase, possibly Yea. The DNA-TraI complex may then interact with the putative coupling protein, TraD, and the DNA is secreted through the T4SS into the extracellular environment. TraK, the predicted secretin, may contribute to pore formation in the outer membrane. TraA is a predicted pilin. EppA is an endopeptidase that could potentially degrade peptidoglycan to allow for apparatus formation in the periplasm. Proteins depicted in black show differences between meningococci and gonococcal strain MS11, while proteins in gray are similar. OM, outer membrane; PG, peptidoglycan; IM, inner membrane.