Fig. 2: Analysis of PP1c/PP2Ac amino acid preference using the PLDMS approach.
a PP1c and PP2Ac preferably dephosphorylate pThr over pSer. For statistical analysis, a two-sided Fisher’s exact test was used. b Heat-map analysis of the sequence context surrounding pSer/pThr dephosphorylated by PP1c and PP2Ac. Color coding: Phosphorylation-fold-change of all amino acids compared to the average library dephosphorylation. At 1 the dephosphorylation rate of an amino acid is equal to the average dephosphorylation rate. For a third heat map comparing PP1c and PP2Ac, dephosphorylated peptides for each amino acid were divided and Nterm/Cterm heat-maps were normalized by the median. To allow better visualization by color coding, Pro in+1 was excluded. Fold-changes >1.2 with an adjusted p-value <0.01 according to Fisher’s exact test in the comparison of PP1c/PP2Ac are highlighted in bold. Please see the methods section and Source Data for details on statistics. c Analysis of the additive influence of positive and negative charges on dephosphorylation by PP1c/PP2Ac of Nterm/Cterm libraries. p-Values were derived by carrying out a two-sided Fisher’s exact test. Exact p-values are provided in the Source Data. d, e Kinetic analysis of the dephosphorylation rate of four synthetic peptides upon PP2Ac or PP1c treatment. Error bars represent s.e.m. of three independent repeats with technical duplicates. kcat/Km was calculated by comparison to a phosphate standard curve. Source data underlying Fig. 2a–e are provided as a Source Data file.
