Part of the ABC transporter complex YclNOPQ involved in uptake of ferric-petrobactin. Petrobactin is a photoreactive 3,4-catecholate siderophore produced by many members of the B.cereus group, including B.anthracis. Binds selectively iron-free and ferric petrobactin and the petrobactin precursor 3,4-dihydroxybenzoic acid (3,4-DHB). The complex is composed of two ATP-binding proteins (YclP), two transmembrane proteins (YclN and YclO) and a solute-binding protein (YclQ) (Probable). Interacts with FloT (PubMed:23651456). Also found in the extracellular protein fraction (PubMed:10658653). May exist in both membrane-tethered and soluble form (Probable). Present in detergent-resistant membrane (DRM) fractions that may be equivalent to eukaryotic membrane rafts; these rafts include proteins involved in signaling, molecule trafficking and protein secretion (PubMed:23651456). Disruption mutants are unable to use petrobactin for iron delivery and growth. Belongs to the bacterial solute-binding protein 8 family.