Zinc metalloproteinase which cleaves human immunoglobulin A1 (IgA1) in the hinge region, rendering it less efficient in coating the surface of colonizing or invading pneumococci. Strongly contributes to virulence in mice. May be responsible for pneumococcal infection and is potentially involved in distinct stages of pneumococcal disease. Cleavage of Pro-|-Thr bond in the hinge region of the heavy chain of human IgA. Binds 1 zinc ion per subunit. The Gram-positive cell-wall anchor motif LPXTG is located in the N-terminal part, in contrast to such motifs in other known streptococcal and staphylococcal proteins. The protease could be cleaved by the sortase and anchored in the membrane via the two potential N-terminal transmembrane domains, whereas the propeptide located prior to the LPXTG motif would remain attached to the cell wall peptidoglycan by an amide bond (By similarity). Belongs to the peptidase M26 family.