Figure 3. Sequence of the A17 immunodominant region from the cagA gene (Helicobacter pylori Chilean strain CH-CTX1) compared to equivalent A17 regions taken from sequences available at GenBank. Sequences are from strains ATCC 43526 Acc# ABO15413, NCTC 11637 Acc# ABO15416, J194 Acc# ABO17921, 26695 GI: 2313664 , GC401 GI:6573220, J99 Acc# NP223213, J187 Acc# ABO15406, and CCUG 17874 Acc# X70038 and X70039. The sequences were aligned with respect to the longest sequence (ATCC 43526 strain). Absent amino acids are indicated by dashes (-) and identical amino acids by asterisks (*). Amino acid differences are indicated. Repeated EPIYA tracts containing putative tyrosine phosphorylation sites are underlined and in bold face. Other repeated elements are also underlined. Positions 1 and 268 of the A17 from strain CH-CTX1 correspond to position N747 and E977 of the CagA sequence derived from strain CCUG 17874. Clone 16 encoding the A17 region from CH-CTX1 contains a methionine initiator triplet and a stop codon after amino acid position 268.