Specific chaperone for cognate PE/PPE proteins. Plays an important role in preventing aggregation of PE/PPE dimers. Interacts specifically with ESX-5-dependent PE/PPE proteins. Forms a 1:1:1 heterotrimeric complex with the PE25/PPE41 dimer, via PPE41. Binding of EspG5 does not cause conformational changes in the PE25/PPE41 dimer. Deletion does not affect EsxN and PPE41 secretion. Belongs to the EspG family.