Part of the ESX-3 specialized secretion system, which is required for siderophore-mediated iron acquisition and for the secretion of EsxH and EsxG (PubMed:19846780, PubMed:24803520). EccA3 exhibits ATPase activity and may provide energy for the export of ESX-3 substrates (By similarity). Part of the ESX-3 / type VII secretion system (T7SS), which is composed of cytosolic and membrane components. Belongs to the CbxX/CfxQ family. Truncated N-terminus.