Figure 4.

The molecular mass of PTYR changes according to the molecular mass of the CagA antigen. Wild-type (wt) strains G27 and 342 and their isogenic cagA knockout mutants were incubated with AGS cells (12). Proteins were analyzed by SDS/6% PAGE and probed with anti-PY or with monoclonal anti-CagA antibody (LDS 56) by Western blotting. The mobility of CagA was estimated by SDS/PAGE and was also inferred by DNA sequence analysis of the 102-bp repeat region. The presence of two repeats in strain G27 and one repeat in strain 342 allowed precise calculation of the size of CagA and explains the kDa difference.