Nucleotide binding by chimeric and wild-type TAP constructs. (A) Cells expressing the indicated TAP constructs were lysed, immunoprecipitated with anti-his (lanes 1 and 5), or incubated with ATP (lanes 2 and 6), ADP (lanes 3 and 7) or AMP-agarose (lanes 4 and 8) beads, followed by immunoblotting analyses with anti-his. (B–F) Same procedure as in A was followed except that the microsome preparations rather than cell lysates were used to compare expression levels. Immunoblotting analysis was carried out with (B) anti-TAP2, (C and E) Pep3, and (D and F) 435.3.