FIGURE 6.

A novel termination readthrough peptide observed at the C-terminus of the SBP-p53 fusion protein. The MS/MS spectrum is representative from Figure 4A (row 8b, columns 1, 2, 3, 5, and 6). The table shows ion matches (red are y-ions and blue are b-ions). Further parameters from the measurement and evaluation are: scan: 7,129; −10lgP PEAKS peptide score: 49.86; mass of the precursor peak: 1871.87, m/z 936.94 (z = 2); error in ppm: 0.9; RT 17.38 min. The sequence of the C-terminus is shown with “SBP STOP AT C TERMINUS” that would form the sequence if an amino acid was placed at the termnination codon. The sequence of the C-terminus is also shown with the “SKIP STOP” reference sequence database where we can observed the indicated peptide sequence resulting in the termination codon skipped during translation and then in-frame translation to the next termination codon ending with the amino acid Cysteine.