FIGURE 2.

Binding of AmiA, AliA, and AliB to their peptide ligands. Binding of recombinant AmiA (A–E), AliA (F–I), and AliB (J–M) to the peptides shown was determined by intrinsic tryptophan fluorescence-binding assay. A drop in fluorescence indicates binding. Peptide sequences are indicated above the arrows marking the point of their addition to the protein. A representative of three independent experiments, performed on different days, is shown. AmiA bound its predicted ligand (A) but also the ligands of AliA (B) and AliB (C) but not the ligands of AliB-like ORF 1 (D) and AliB-like ORF 2 (E) which acted as negative controls. AliA also bound its predicted ligand (F) but not the negative controls (G,H). There was also a drop in fluorescence upon exposure to its ligand with one amino acid change (underlined) (I) although this was less evident than in (F). AliB also bound its predicted ligand (J) but neither of the negative controls (K,L) or to a great extent to its ligand with one amino acid change (underlined) (M).