Fig. 2.

Tyrosine nitration of AAG decreases excision activity. (A) Tyrosine nitration of AAG following ONOO⁻ treatment (Materials and Methods). Purified wild-type AAG was treated with ONOO⁻ (10, 20, 40 and 100 μM). Nitrotyrosines and AAG were detected on separate membranes with an anti-nitrotyrosine (upper) and anti-AAG (lower) antibody, respectively. (B) Western blot showing metal-catalyzed tyrosine nitration of AAG. Purified wild-type AAG was incubated with NaNO₂ and H₂O₂; the sample loaded in the left lane (−) lacked FeSO₄, whereas the sample in the right lane was incubated with 2 μM FeSO₄. (C) Hanes–Woolf plot of εA excision by ONOO⁻-treated AAG. After ONOO⁻ treatment, AAG (1 nM) was incubated with εA-containing DNA (5–25 nM) for 60 min. Data are a mean of six independent experiments.