title: Forbidden penta-peptides.
abstract: There are 3,200,000 amino acid sequences of length 5 (penta-peptides). Statistically, we expect to see a distribution of penta-peptides that is determined by the frequency of the participating amino acids. We show, however, that not only are there thousands of such penta-peptides that are absent from all known proteomes, but many of them are coded for multiple times in the non-coding genomic regions. This suggests a strong selection process that prevents these peptides from being expressed. We also show that the characteristics of these forbidden penta-peptides vary among different phylogenetic groups (e.g., eukaryotes, prokaryotes, and archaea). Our analysis provides the first steps toward understanding the "grammar" of the forbidden penta-peptides.
authors: School of Computer Science, Tel Aviv University, Tel Aviv, Israel. tamirtul@post.tau.ac.il
authors: Tamir
authors: T
authors: Tuller
authors: Benny
authors: B
authors: Chor
authors: Nathan
authors: N
authors: Nelson
mesh_terms: D000818:Animals; D001105:Archaea / Q000235:genetics; D001419:Bacteria / Q000235:genetics; D021901:DNA, Intergenic / Q000737:chemistry; D009842:Oligopeptides / Q000737:chemistry* / Q000235:genetics; D010802:Phylogeny; D040901:Proteomics; D020539:Sequence Analysis, Protein
chemical_list: D021901:DNA, Intergenic; D009842:Oligopeptides