FIG. 6. Sequencee of three peptides derived from affinity purified H2TF1 match sequences contained in NF-κB2 p100.

H2TF1, twice purified by DNA affinity chromatography on an MHC κB column, was electrophoresed by SDS-PAGE, transferred to a nitrocellulose filter, and digested with trypsin as described under “Materials and Methods.” The resulting tryptic peptides were purified by HPLC on a C18 silica column. Three nontrypsin peptides were sequenced by Edman stepwise degradation on an Applied Biosystems 477A pulse liquid protein sequenator. The sequences of the peptides are given above, following the arginine/lysine residue at the site of trypsin cleavage. Of note, peptides 2 and 3 were present as a mixture in a single HPLC absorbance peak, and were distinguished from each other on the basis of relative molar yields. The beginning of each tryptic peptide sequence is indicated by K/R indicating by inference the lysine or arginine amino acid residue preceeding trypsin cleavage. Indeterminant amino acid residues are indicated by X. Where there was sequence ambiguity between 2 amino acids, both are listed. The amino acid sequences determined unambiguously matched the predicted amino acid sequence inferred from cDNA sequence of the nfkb2 gene (Schmidt et al., 1991; Neri et al., 1991; Bours et al., 1992), with two exceptions noted under “Results.” The amino acid residue numbers of the H2TF1 peptides are amino acids 460–471 of NF-κB2 pl00 for peptide 1, 579–597 for peptide 2, and 635–647 for peptide 3 (the numbered residues beginning with the residue following arginine).