FIG. 2.

Structures and properties of IκBα mutants. The structure of IκBα, comprised of an N-terminal domain (stippled box), ankyrin repeats (hatched boxes), and a C-terminal region (open box) containing a PEST domain (black box), is depicted (not to scale). C-terminal deletion mutants Δ267, Δ282, Δ285, Δ287, Δ301, and 76-284 were generated by introducing stop codons. Translation start codons were introduced at position 75 in mutants 76-318 and 76-284. Mutant A5 contains alanine substitutions for the serines at positions 287, 292, 293, and 295 and the threonine at position 300 of IκBα. Mutant Δ287-295 has an internal deletion of nine amino acids in the C-terminal PEST domain of IκBα. Mutants Δ285-Tail 4 Glu, Δ285-Tail 2 Asp, and Δ285-Tail 4 Ala, respectively, have Glu, Asp, and Ala tails added to the C terminus of mutant Δ285. nd, not determined.