Transpeptidase that anchors surface proteins to the cell wall. 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. This sortase recognizes a Leu-Pro-x-Thr-Gly (LPXTG) motif, which is cleaved by the sortase between the threonine and glycine residues (By similarity). Essential for adherence to eukaryotic cells and for binding to fibronectin and fibrinogen (PubMed:15908360). Mutant is unable to anchor the C5a peptidase (ScpB) and Alp2 to the cell wall. Mutant is also impaired for binding to the major extracellular matrix components fibronectin and fibrinogen and displays a significant reduction in adherence to human and murine epithelial cells. Inactivation of the gene has no effect on the virulence in a neonatal rat model but strongly impairs the capacity of the strain to colonize the intestines of gnotobiotic mice in a competition assay. Belongs to the bacterial sortase family. Class A subfamily.