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Nonrandom tripeptide sequence distributions at protein carboxyl termini
Gregory J Gatto1, Jeremy M Berg
1Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Genome Research
|April 3, 2003
Summary
Analyzing C-terminal tripeptides in genomes reveals distinct patterns between prokaryotes and eukaryotes. Eukaryotic genomes show overrepresented sequences, suggesting novel functional roles in protein targeting and translation.
Area of Science:
- Genomics
- Molecular Biology
- Bioinformatics
Background:
- Complete genome sequences allow unbiased statistical analysis of sequence features.
- Carboxyl termini of proteins are crucial for protein targeting and translational termination.
Purpose of the Study:
- To analyze the frequency of C-terminal tripeptides across archaeal, bacterial, and eukaryotic genomes.
- To identify overrepresented tripeptide sequences in eukaryotic genomes and explore their potential functions.
Main Methods:
- Statistical analysis of C-terminal tripeptide frequencies in complete genome sequences.
- Comparison of observed tripeptide distributions with randomized sets.
Main Results:
- Prokaryotic genomes exhibit tripeptide distributions similar to random sets.
- Eukaryotic genomes display significant overrepresentation of specific C-terminal tripeptides.
- Identified known targeting signals and enhanced translational termination sequences.
- Discovered novel overrepresented tripeptides, such as XSS in plants and FWC in yeast.
Conclusions:
- Eukaryotic C-terminal tripeptide composition is non-random and enriched for functional elements.
- Overrepresented tripeptides may indicate novel mechanisms for protein targeting, processing, or translational control.
- Further investigation into these novel sequences could uncover new biological functions.