Genes in our DNA encode proteins using triples of four chemicals whose names begin with A, T, C and G. When a gene is being transcribed into a protein, each triple (such as A.C.T, A.G.C and G.T.A) is mapped to one of 20 amino acids, with T.A.A, T.A.G and T.G.A all meaning "end of sequence". Note that although a triplet could theoretically map to one of 4x4x4=64 different amino acids, several triples map to the same amino acid. The net result is that every protein is created out of a sequence of amino acids.
According to this article in The Economist, scientists are extending the genetic code by introducing more letters and mappings to the genetic language. Specifically, a new "letter" 3-FB has been added, allowing proteins to be made out of triples built from a larger vocabulary, such as A.C.3-FB and G.3-FB.C. The addition of this new letter allows new kinds of "alien" proteins to be encoded that utilize more than the original 20 amino acids. Note that this approach is backwards compatible with existing cellular machinery.
The article doesn't speculate on what the uses of expanded proteins might be, but it's fascinating to know that we're tinkering with the very fabric of life.
nice !!!
Posted by: glass | Mar 22, 2005 at 03:10 AM
Great Stuff!
Posted by: DNA Book | Mar 23, 2005 at 10:40 AM