New recipe for novel proteins

Yale researchers have discovered a targeted way to make proteins not generally found in nature by expanding the information encrypted in the genetic code. Working with bacteria, the Yale team rewrote most of the genetic instructions that encode all 20 amino acids - the building blocks of any protein - to create a specific, 21^st amino acid, researchers report in the January 2014 issue of the journal Angewandte Chemie. The finding adds another method to quest of synthetic biologists goal of expanding life's genetic code to produce novel proteins that do not exist in nature but may be valuable for a wide variety of industrial, medical or pharmaceutical purposes. "Achieving this would open the doors to a whole new world of designer proteins with novel catalytic and mechanistic properties and possibly even biomedical applications,'' said Markus Bröcker, postdoctoral associate in molecular biophysics and biochemistry at the Yale School of Medicine and lead author of the paper. The authors used a decoding system that occurs naturally in the cell to insert the information for the additional amino acid selenocysteine, the 21^st amino acid. Living organisms use 64 different codons - or combinations of three of the four nucleic acids that comprise DNA - as the basis for the 20 amino acids that are found in regular proteins. To test whether they could change this genetic recipe, the Yale team took advantage of the extra molecular decoding step involved only in the insertion of the amino acid selenocysteine into proteins.