FIGURE 3.

Identification of Serpinb6b as a potential mouse granzyme A inhibitor. Alignment of all human (A) or mouse (B) clade B serpins with a predicted P1 Arg or Lys. Basic residues are shown enlarged in bold. C, peptide substrate specificity derived from phage display for mGzmA and hGzmA aligned to the Serpinb6b reactive center loop sequence. Strongly selected (>4σ) residues are shown in uppercase, and weakly selected residues (2σ to 4σ) are in lowercase. D, interaction of hGzmA with human clade B serpins. Serpins were expressed in COS-1 cells as GFP fusions and cell lysates incubated with or without hGzmA. Reactions were resolved by 10% SDS-PAGE and immunoblotted with a monoclonal GFP antibody.