Proteolytic digestion identified a specifically protected region of PcrV in presence of PcrG. A. and B. Proteolytic digestion profiles of PcrV and PcrG-PcrV, respectively, with α-chymotrypsin from 10 to 50 minutes. Black arrows indicate the stable fragments generated after proteolysis. C. The digestion patterns of PcrV and PcrG-PcrV shows the presence of a specifically protected region of PcrV in the PcrG-PcrV complex, which is highlighted by a black arrow and a red star. L1 and L2 denote native PcrV and PcrG-PcrV. L3 and L4 denote PcrV and PcrG-PcrV, respectively, cleaved by α-chymotrypsin after 30 minutes. M is the protein molecular weight marker (10, 17, 26, 34, 43, 55 kDa bands from bottom to top).