Fig. 2: Mapping the human Nt-acetylome.
a The prevalence of Nt-acetylation in human cells is visualized by separating the proteome into the Nt-acetylome (80%) and the non-Nt-acetylome (20%). The human Nt-acetylome was predicted by incorporating experimentally determined Nt-acetylation events (including NatC-47 and NatF-56related data) to all SwissProt entries (version 57.8) based on the occurrence of the first two amino acids. Note that this global estimate does not consider the distinction between full and partial Nt-acetylation. Thus, a given protein can exist in both Nt-acetylated and non-Nt-acetylated forms. The chance that your favorite protein will be Nt-acetylated mainly depends on the identity of the first two amino acids. To visualize this concept, the Nt-acetylome can be grouped according to b NAT substrate class and/or c N-terminal amino acid frequency. For example, NatB-type substrates (MD-, ME-, MN- MQ-) are almost fully Nt-acetylated and account for 21% of the proteome. The combined NatC/E/F substrate class needs further refinement, which is reflected by a coverage rate of 75%. For example, an estimated 89% of ML-starting N-termini are Nt-acetylated, which is in stark contrast to MK- starting N-termini, where only 54% of N-termini are thought to be Nt-acetylated. MW- and MR- data are inferred based on structural similarity to MF- and MK-, respectively. NatD is not depicted due to its limited coverage
