Comparison of streptococcal IgA1 protease sequences. The protein region to which peptides epiA and epiB correspond to amino acids 420–493 of the IgA1 protease of S. pneumoniae R6. The amino acid sequences are from S. pneumoniae type 2 strain R6 (U47687, Q54875), the type 4 strain TIGR4 (NC_003028), and the type 19F strain G54 (AL449925). The sequence of the type 6B strain 670 is from the TIGR Website . BLAST comparisons to further sequences were done on the Sanger Website for the type 1 strain INV104B, the type 3 strain OXC141, the type 14 strain INV200 and the type 23F strain Spanish 23F-1 . The S. mitis sequence is from GenBank AAY40355. Identical amino acid sequences are in white letters on a black background.