Part of the ABC transporter complex NikABCDE (Opp2) involved in nickel import. Probably responsible for the translocation of the substrate across the membrane. Required for full urease activity and plays a significant role in the virulence of S.aureus during urinary tract infection (UTI). The complex is composed of two ATP-binding proteins (NikD and NikE), two transmembrane proteins (NikB and NikC) and a solute-binding protein (NikA). Transcription is stable during the exponential phase and increases only in standard conditions in late exponential phase. Deletion of the nikBCDE operon strongly reduces nickel transport and urease activity. Mutant shows decreased virulence in a mouse model of ascending UTI (PubMed:20662775). Insertion mutant shows attenuated growth in several infection models (PubMed:9791183). Belongs to the binding-protein-dependent transport system permease family. OppBC subfamily.