FIGURE 2.

Binding of the cytosolic domain of Tom20, Tom22, and Tom70 to a peptide array derived from APE1. Binding of 150 nm Tom20cd (A), Tom22cd (B), and Tom70cd (C) to a peptide array consisting of 15 residues derived from APE1. The first peptide comprises amino acids 1–15 of APE1, the second peptide comprises residues 4–18, the third peptide comprises residues 7–21, and so on. The labeling originated from the peptide array. A quantitative measure of the binding strength was performed with Spotfinder software, which included subtraction of the local background for each peptide spot. The values for different membranes were adjusted by the use of identical reference peptides on each membrane. Results were obtained from three independent experiments. Tom proteins were immobilized by cobalt chelate and then incubated with HeLa cell extracts (D). The eluants from each Tom protein His tag pull-down experiment were separated using SDS-PAGE and then subjected to anti-APE1 antibody using Western blot (IB). The complete cellular extraction of the HeLa cell was also added as an input. As shown in Fig. 4, only Tom20cd interacted with APE1 from the HeLa cell extraction.