Protein interaction on AminoLink column. (A) LtxA was immobilized on an AminoLink column. Lanes: 1, input LtxA (4 μg); 2, column flowthough. (B) Interaction between immobilized LtxA and proteins from A. actinomycetemcomitans strain JP2 extract. Lanes: 1, input JP2 cell extract (10 μg); 2 and 3, column wash; 4 to 6, elutions. The arrow indicates the 18-kDa protein band. (C) Bovine Cu,Zn SOD interaction control. Lanes: 1, input bovine Cu,Zn SOD (2 μg); 2 and 3, column wash; 4 to 6, elutions. All gels were stained with Coomassie blue. Molecular mass standards are in kDa.