Scientific background

Extraction

Sequences were truncated to their N-terminal 40 residues and subsequently homology reduced by visual inspection of a neighbour-joining tree generated from a ClustalW multible alignment. Four sequences were removed from the positive dataset due to close homology to other sequences and following this reduction the two closest homologs were 52% identical although the average homology is much lower.

Below is shown an unrooted phylogenetic tree of the positive data set before homology reduction.

Below is shown an unrooted phylogenetic tree of the negative data set before homology reduction.

To visualise the sequence information content for N-terminal acetylation, we have generated sequence logos for the yeast training set. The total height of the stack of letters at each position shows the amount of sequence conservation at the position, while the relative height of each letter shows the relative abundance of the corresponding amino acid.