Identification and Functional Characterization of N-Terminally Acetylated Proteins in Drosophila melanogaster
Figure 2
Analysis of translational start sites.
(A) A Frequency analysis [54] of all predicted N-termini present in the Drosophila database BDGP_Release_3.2 revealed the presence of the Cavener consensus sequence C_A/G_A_A/C_ATG [25],[26]. The histogram shows the relative frequencies of nucleotides 5′ to the predicted (conventional) initiator codon generating acetylated as well as non-acetylated N-termini starting at position 1 or 2 of the predicted protein sequence. The nucleotide 3′ of the initiator sequence has been proposed to preferentially be a G at +4 [55] for strong initiation but has been shown not to be relevant for Drosophila [25],[26]. Interestingly the G at +4 is nevertheless predominant in all cases. (B) Relative frequencies of nucleotides 5′ to the alternative translation initiation sites. The Cavener sequence is conserved showing a shift in sequence preference at position −1 (from A to C), which fully complies with the Cavener consensus sequence (C_A_A_C_ATG) [25],[26].