| METHOD |
The molecular building set of all living species “is nearly invariant”. “Yet it is seldom asked why it is not otherwise – why was this particular set of amino acids & nucleotides chosen & maintained over geological times? A straight forward approach to this issue is to generate a artificial biodiversity deviating from the invariant building scheme? Authors accomplish this by utilizing the tendency of tRNA synthetases to make mistakes – that is, to catalyze the addition of incorrect amino acids to tRNA. Most synthetases have a editing site that reverses such errors. But the researchers identified bacteria that express a mutant valine synthetase that lacks this editing ability. The synthetase thus catalyzes the addition of valine analogs to tRNA without any subsequent correction of the substitution. The researchers selected the editing mutants by using a nutritional screen, showing that “natural selection can be applied to evolve the genetic code experimenta lly”. They found that bacteria expressing the mutant synthetase incorporate the valine analog ALPHA-AMINOBUTYRATE into 24% of sites normally occupied by valine. “We believe this is a starting point toward 100% replace ment” author says. Advantage of this approach is its simplicity. “Namely, it produces sweeping general changes in all cellular proteins through a single mutation in the editing site of just one tRNA synthetase. As a consequence, novel organisms that use unnatural amino acids will now be easily generated. And it is not far from there to producing novel protein-based biomaterials with all sorts of new aminoacids |
| UPDATE | 05.01 |
| AUTHOR | This data is not available for free |
| LITERATURE REF. | This data is not available for free |
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