PNAs breakthrough! Scientists use quantum chemistry to reveal why life is made up of 20 amino groups

A team led by Dr Matthias granold, Department of pathobiochemistry, University of Mainz, Johannes Gutenberg, and Professor Bernd Moosmann used quantum chemistry to solve one of the oldest puzzles in biochemistry They explained why life today is made up of 20 amino acids They also found that through the first 13 amino acids, they can make functional proteins The decisive factor lies in the greater chemical activity of new amino acids, not in their new structure The research was published in PNAS recently The researchers also speculated that the increase of oxygen content in the atmosphere resulted in the increase of amino acids in the protein Institute All life on earth is based on 20 amino acids DNA synthesizes proteins by controlling amino acids DNA needs three bases to encode an amino acid "Researchers have been wondering why evolution chose these 20 amino acids for gene coding." Professor Bernd Moosmann said "The latest seven amino acids are the most difficult to explain, because only the first 10-13 amino acids can form the protein we need." In the new study, the researchers compared the quantum chemical properties of the 20 amino acids that make up life, other amino acids from space, and modern reference biomolecules They found that new amino acids became softer - more active or more reactive "The biggest change from the ancient chemicals in space to our biochemistry today is that amino acids are more flexible, so they have higher reactivity to form proteins." Bernd Moosmann explains The researchers also verified the results of their theoretical calculations through biochemical experiments However, there are still some problems to be solved: for example, why are these soft amino acids not the first ones to enter the toolbox? What do these amino acids react with? Based on their results, the researchers believe that at least some new amino acids, especially methionine, tryptophan and selenocysteine, are due to increased oxygen levels in the atmosphere Oxygen promotes the formation of toxic free radicals, which brings a lot of oxidative stress to organisms and cells These new amino acids can react with free radicals to effectively capture them These new amino acids can be easily recovered after being oxidized, so as to protect the important biological structures which are difficult to repair after oxidative damage Therefore, the new amino acids have brought advantages to the survival of ancient creatures They can survive in an environment with stronger oxidation capacity, thus bringing a new world to the earth "From this point of view, we can think of oxygen as building blocks for genetic code."