Part of the ABC transporter complex IrtAB involved in the import of iron-bound mycobactin (Fe-MBT) and carboxymycobactin (Fe-cMBT) (PubMed:16385031, PubMed:19948799) (By similarity). Mycobactins are then reduced by the siderophore interaction domain to facilitate iron release in the bacterial cell (By similarity). Transmembrane domains (TMD) form a pore in the membrane and the ATP-binding domain (NBD) is responsible for energy generation (By similarity). Required for replication in human macrophages and in mouse lungs (PubMed:16385031). Forms a heterodimer with IrtB. Repressed by iron and IdeR. In IrtA the ATP-binding domain (NBD) and the transmembrane domain (TMD) are fused (PubMed:16385031). In addition, IrtA contains an N-terminal siderophore interaction domain (SID) that binds FAD (PubMed:19948799). Belongs to the ABC transporter superfamily. Siderophore-Fe(3+) uptake transporter (SIUT) (TC 3.A.1.21) family. PubMed:18461140 reports that IrtA is a siderophore exporter, however this activity could be due to functional differences of IrtA in the molecular context of M.smegmatis and M.tuberculosis.