Figure 1.

Prevalence of amino acids in the second positions of proteins initiated by a Met residue in selected species. Panels A-D illustrate the distribution of second position amino acids for selected representatives of each of the evolutionary groups. A. Bacteria, represented by E. coli (n=4,474). B. Unicellular eukaryotes, represented by S. cerevisiae (n=4,819). C. Animals, represented by H. sapiens (n=10,790). D. Plants, represented by A. thaliana (n=3,056). Representative groups were selected based on the largest amount of protein sequences present in the Swiss-Prot database. Black columns are the most abundant second position amino acids. White columns are the next most abundant amino acids.