Fig. 2.

(A) a 2D-gel (20 × 20 cm, pH 5–8) showing all proteins bound by metronidazole and tinidazole. (B) close-up of the affected proteins in untreated cells, and in cells either treated with 10 μM metronidazole (Mz), 50 μM metronidazole, or 50 μM tinidazole (Tz) for 2 h. Covalent adducts of metronidazole and tinidazole are visible as newly appearing protein spots containing the affected protein shifted to a more basic pI (to the right). Shifted portions of proteins are indicated by arrows. In the case of proteins 6 and 7, the original spots are indicated by continuous circles and shifted portions by broken circles. Some of the protein shifts with tinidazole (proteins 5, 8, and 9) are so narrow that no new distinct spots containing tinidazole-bound protein are discernible. Instead, the original spots are extended to a more basic pI. The numbers refer to the following proteins: (1) thioredoxin reductase; (2) alpha-11 giardin; (3) β-giardin; (4) Giardia trophozoite antigen 2; (5) branched-chain amino acid transferase; (6) and (7) elongation factor-1γ; (8) pyruvate phosphate dikinase; (9) alcohol dehydrogenase. For details see Table 1.