Genetic Code 2.0
A new approach to the use of genetic material has been opened, which will allow the creation of proteins with properties unseen in the natural environment. The discovery may someday lead to the creation of a new or "improved" life form that will absorb these new materials.
In all existing life forms, the four “letters” of the genetic code, called nucleotides , are read as triplets, so that the three nucleotides encode the amino acid.
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But it was like this before ... Jason Chin and his colleagues at the University of Cambridge redesigned cellular mechanisms so that they read the genetic code by quadruplets (in other words, 4 ).
In the genetic code that life has used to this day, there are 64 possible combinations of triplets of 4 nucleotide letters. These genetic "words" are called codons. Each codon either encodes an amino acid or tells the cell to stop the production of the protein chain. Now, the Chin team created 256 empty four-letter codons that can be “assigned” to amino acids that do not even exist yet. ( Comment of translator: it should be understood that nucleotides encode amino acids not because they are chemically bound, but because the ribosome, like a compiler, "knows" all 64 codes and knows how to create an amino acid corresponding to the code. Therefore, the new 256 combinations are "empty" The normal ribosome does not know what to do with these codes. They must be “assigned” )
To achieve this result, the team had to rebuild several cellular mechanisms for the production of proteins. But they did not stop at getting a working system. To prove that the final genetic code works, they “assigned” the quadruplet codons to the two “unnatural” amino acids and incorporated them into the real protein chain.
According to Chin, "This is the beginning of a parallel genetic code."
However, what is more interesting is that these two amino acids can react with each other, forming different types of chemical bonds, including those that usually join proteins during the formation of their three-dimensional structure.
The usual type of bonds - disulfide - can be broken by changing the temperature or acidity, as a result of which proteins lose their three-dimensional shape. For example, a chicken egg changes its texture and color during the preparation precisely because of this process : albumin in a protein ( egg white ) loses its three-dimensional structure and its physical characteristics change.
But new amino acids create stronger bonds and therefore proteins formed from them can work in a much wider range of temperatures and environments, which, for example, can help create medicines that will not break down in untargeted places in the gastrointestinal tract.
"This is a big breakthrough that opens up new theoretical horizons in synthetic biology," said one of the discoverers, Craig Venter, who himself heads the institute in Rockville and is currently working on creating a synthetic organism from a clean slate.
In all existing life forms, the four “letters” of the genetic code, called nucleotides , are read as triplets, so that the three nucleotides encode the amino acid.
')
But it was like this before ... Jason Chin and his colleagues at the University of Cambridge redesigned cellular mechanisms so that they read the genetic code by quadruplets (in other words, 4 ).
In the genetic code that life has used to this day, there are 64 possible combinations of triplets of 4 nucleotide letters. These genetic "words" are called codons. Each codon either encodes an amino acid or tells the cell to stop the production of the protein chain. Now, the Chin team created 256 empty four-letter codons that can be “assigned” to amino acids that do not even exist yet. ( Comment of translator: it should be understood that nucleotides encode amino acids not because they are chemically bound, but because the ribosome, like a compiler, "knows" all 64 codes and knows how to create an amino acid corresponding to the code. Therefore, the new 256 combinations are "empty" The normal ribosome does not know what to do with these codes. They must be “assigned” )
Fundamental redesign
To achieve this result, the team had to rebuild several cellular mechanisms for the production of proteins. But they did not stop at getting a working system. To prove that the final genetic code works, they “assigned” the quadruplet codons to the two “unnatural” amino acids and incorporated them into the real protein chain.
According to Chin, "This is the beginning of a parallel genetic code."
Strong bond
However, what is more interesting is that these two amino acids can react with each other, forming different types of chemical bonds, including those that usually join proteins during the formation of their three-dimensional structure.
The usual type of bonds - disulfide - can be broken by changing the temperature or acidity, as a result of which proteins lose their three-dimensional shape. For example, a chicken egg changes its texture and color during the preparation precisely because of this process : albumin in a protein ( egg white ) loses its three-dimensional structure and its physical characteristics change.
But new amino acids create stronger bonds and therefore proteins formed from them can work in a much wider range of temperatures and environments, which, for example, can help create medicines that will not break down in untargeted places in the gastrointestinal tract.
"This is a big breakthrough that opens up new theoretical horizons in synthetic biology," said one of the discoverers, Craig Venter, who himself heads the institute in Rockville and is currently working on creating a synthetic organism from a clean slate.
Source: https://habr.com/ru/post/84529/
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