This approach has been able to predict, to our knowledge, all C-terminally anchored targeting motifs present in the literature. Finally, comparative genomics was used to identify tripeptides significantly occurring in multiple species. Similarly, as C-terminal homology among members of large protein families may artificially inflate tripeptide counts in an irrelevant and obfuscating manner, gene-family clustering was performed prior to the analysis in order to assess tripeptide over-representation across protein families as opposed to across all proteins. Sequence randomization models and simple-sequence masking were applied to the successful reduction of background noise. Results We examined the statistical over-representation of position-specific C-terminal tripeptides in 7 eukaryotic proteomes.

We have applied a novel methodology to the prediction of C-terminal-anchored peptide motifs involving a simple z-statistic and several techniques for improving the signal-to-noise ratio. As a limited number of such motifs have been identified, the potential exists for genome-wide statistical analysis and comparative genomics to reveal novel peptide signatures functioning in a C-terminal dependent manner.

Several short peptide motifs involved in protein sorting roles and dependent upon their proximity to the C-terminus for proper function have already been characterized. C-terminal motif prediction in eukaryotic proteomes using comparative genomics and statistical over-representation across protein familiesĭirectory of Open Access Journals (Sweden)įull Text Available Abstract Background The carboxy termini of proteins are a frequent site of activity for a variety of biologically important functions, ranging from post-translational modification to protein targeting.

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