Figure 3.

Modification of the cysteine proteases, Lys-gingipain (Kgp; antigen no. 25) and Arg-gingipain (RgpA; antigen no. 27) to inhibit their proteinase activities. Cysteine residues were substituted with alanine residues on C477 of recombinant Kgp and C471 on recombinant RgpA. (A) SDS-PAGE analysis of the mutant recombinant proteins. Approximately, 50 ng of each recombinant protein was loaded into each lane. (B) Serum IgG responses to the mutants as determined by the dot blot analysis. Approximately, 50 ng of each protein was blotted on the membrane, and sera were used at a dilution of 1:2,500.