Figure 1. S. pneumoniae strain SP168 harbors a truncated zmpC gene.

A) Two independent genomic DNA isolates (1 & 2) from S. pneumoniae strains SP168 and TIGR4 were used as templates in polymerase chain reactions along with zmpC-specific primers. Amplified products were resolved on a 1% agarose-TBE gel. DNA molecular weight markers are indicated in kilobase pairs on the left of the gel. B) Representation of the predicted domains within the SP168 and TIGR4 ZmpC proteins as determined by the Conserved Domain Database (http://www.ncbi.nlm.nih.gov/Structure/cdd/cdd.shtml). YS: YSIRK type signal peptide; G5: G5 domain; P_M26_N: M26 IgA1-specific Metallo-endopeptidase N-terminal region; G1: GLUG motif found in IgA1 endopeptidases; P_M26_C: M26 IgA1-specific Metallo-endopeptidase C-terminal region. Descriptions of these domains are included in the results section. The symbol Δ represents deletions within the SP168 ZmpC primary structure. Δ₉₆ and Δ₁₄₄ denote the deletion of 96 and 144 amino acids, respectively, while Δ_ala denotes the deletion of an alanine residue. C) A western blot, using the M11 antibody, on HCLE cell culture supernatants after a 4 h exposure to ZmpC-containing, growth culture filtrates derived from strains SP168 and TIGR4 to assess MUC16 ectodomain cleavage.