NRMT can catalyze the α-N-methylation of DDB2 in vitro.
a, ESI-MS of unmodified forms of the peptide 1APKKRPETQKTS12 without addition of NRMT. b, ESI-MS of the unmodified, mono-, di-, and tri-α-N-methylated forms of the peptide 1APKKRPETQKTS12 with addition of NRMT. c, ESI-MS of the unmodified, mono-, di-, and tri-α-N-methylated forms of the peptide DDB2-P3A (i.e.
1AAKKRPETQKTS12, with the addition of NRMT). d, ESI-MS of unmodified, mono-, di-, and tri-α-N-methylated forms of the peptide DDB2-K4Q (i.e.
1APQKRPETQKTS12, with the addition of NRMT). e, relative abundances of different methylation forms of the N-terminal 12 amino acids of DDB2, DDB2-P3A, and DDB2-K4Q as determined by semiquantitative MS analysis. The results represent the mean ± S.E. of results obtained from three independent experiments. *, p < 0.05; ***, p < 0.001. The p values were calculated by unpaired, two-tailed Student's t test.