Reading through wikis, we may come across parts that we find interesting and potentially helpful in building the next iGEM project. Similar to newspaper clipping, here we write short descriptions of BioBricks and post them up here as an exercise.
- Training cohort: 2015 HKUST iGEM
The P2A peptide sequence is a stretch of amino acid residues (A T N F S L L K Q A G D V E E N P G P) that allows monocistronic mammalian genes to be polycistronic. During mammlian translation, the ribosome running through the codons containing this peptide "skips" the formation of amide bond between the glycine and the proline residue at the C terminus but continue translation on the codons that follow afterwards. As such, it creates an invisible stop codon after the glycine residue and makes the following proline the new de facto start codon. Therefore the peptide is essentially split into half and thus this peptide bears a misnomer as a “self-cleaving” peptide.
The P2A peptide has been known to provide a good alternative to internal ribosomal entry site (IRES), but what it interested me is: the mechanism of action essentially locks the production rates of translation in an equal molar ratio. That would be especially helpful for efficient production of heterodimers / heterocomplexes.