The pneumococcal surface protein proteins, found in Streptococcus pneumoniae, are repetitive, with patterns of localized high sequence identity across pairs of proteins given different specific names that recombination may be presumed. This protein, PspA, has an N-terminal region that lacks a cross-wall-targeting YSIRK type extended signal peptide, in contrast to the closely related choline-binding protein CbpA which has a similar C-terminus but a YSIRK-containing region at the N-terminus.