Transpeptidase that anchors surface proteins to the cell wall (PubMed:11830639, PubMed:15718231, PubMed:24519933) (Probable). Recognizes and modifies its substrate by proteolytic cleavage of a C-terminal sorting signal. Following cleavage, a covalent intermediate is formed via a thioester bond between the sortase and its substrate, which is then transferred and covalently attached to the cell wall (Probable) (PubMed:24519933). This sortase recognizes an Asn-Pro-Gln-Thr-Asn (NPQTN) motif in IsdC, which is cleaved by the sortase between the threonine and aspargine residues; may only have 1 substrate in this bacterium (Probable). May be dedicated to the process of iron acquisition during bacterial infection (Probable). The enzyme catalyzes a cell wall sorting reaction in which a surface protein with a sorting signal containing a NPXTN motif is cleaved between the Thr and Asn residue. The resulting threonine carboxyl end of the protein is covalently attached to a pentaglycine cross-bridge of peptidoglycan. Inhibited by MTSET (2-(Trimethylammonium)-ethyl-methanethiosulfonate) and E64 ([n- (l-3-trans-carboxyoxirane-2-carbonyl)-l-leucyl]-amido(4-guanido)butane) (PubMed:14725770). Inhibited by coptisine (PubMed:29690584). Not expressed in the presence of extracellular iron, repressed by fur in the presence of iron. Loss of cell wall anchoring of IsdC (PubMed:11830639). No effect on establishment of mouse infections, however reduced bacterial persistence after 9 days infection in mice (using strain Newman, which is more pathogenic than RN4220) (PubMed:11830639). Belongs to the bacterial sortase family. Class B subfamily.