Nov 13, 2017 12:17 AM
(This post was last modified: Nov 13, 2017 12:37 AM by Yazata.)
I was reading about this and thought that it was pretty extraordinary.
As most of you probably know, proteins are made of amino acids and some 20 amino acids are coded for by DNA and are found in (Earth) life.
What makes this a bit mysterious is the fact that there are far more amino acids than that, some 500 in total. So why are only this particular set of 20 coded for by DNA? Is it just fortuitous, an accident resulting from the original origin-of-life-events that just happened to produce a genetic coding mechanism for this particular 20? Has all of subsequent life built itself upon that narrow foundation?
So the question arises, could synthetic DNA be engineered that codes for alternative amino acids that are not part of the favored 20? Would that DNA and the cells that contain it survive and sucessfully replicate?
And more speculatively, could expanding the genome's amino acid vocabulary give these synthetic organisms new properties?
I was just reading about work being done on these lines here:
http://schultz.scripps.edu/research.php
Peter Schultz writes:
"The genetic codes of every known organism specify the same 20 amino acid building blocks using triplet codons generated from A, G, C and T. These twenty amino acids contain a limited number of functional groups including acids, amides, alcohols, basic amines and thiols. Is this the ideal number or would additional amino acids allow the generation of proteins or even entire organisms with enhanced properties?...
...To this end, we have developed a methodology that allows one to genetically encode novel amino acids, beyond the common twenty, in both prokaryotic and eukaryotic organisms."
See also:
https://en.wikipedia.org/wiki/Expanded_genetic_code
https://en.wikipedia.org/wiki/Peter_G._Schultz
"This is accomplished by screening libraries of mutant amino acyl tRNA synthetases for mutants which charge nonsense-codon tRNAs with the desired unnatural amino acid. The organism which expresses such a synthetase can then be genetically programmed to incorporate the unnatural amino acid into a desired protein in the usual way, with the nonsense codon now coding for the unnatural amino acid...
More than seventy unnatural amino acids have been genetically encoded in bacteria, yeast, and mammalian cells, including photoreactive, chemically reactive, fluorescent, spin-active, sulfated, pre-phosphorylated, and metal-binding amino acids. This technology allows chemists to probe, and change, the properties of proteins, in vitro or in vivo, by directing novel, lab-synthesized chemical moieties specifically into any chosen site of any protein of interest."
Don't be surprised if you see this work winning a Nobel prize sometime in the future.
As most of you probably know, proteins are made of amino acids and some 20 amino acids are coded for by DNA and are found in (Earth) life.
What makes this a bit mysterious is the fact that there are far more amino acids than that, some 500 in total. So why are only this particular set of 20 coded for by DNA? Is it just fortuitous, an accident resulting from the original origin-of-life-events that just happened to produce a genetic coding mechanism for this particular 20? Has all of subsequent life built itself upon that narrow foundation?
So the question arises, could synthetic DNA be engineered that codes for alternative amino acids that are not part of the favored 20? Would that DNA and the cells that contain it survive and sucessfully replicate?
And more speculatively, could expanding the genome's amino acid vocabulary give these synthetic organisms new properties?
I was just reading about work being done on these lines here:
http://schultz.scripps.edu/research.php
Peter Schultz writes:
"The genetic codes of every known organism specify the same 20 amino acid building blocks using triplet codons generated from A, G, C and T. These twenty amino acids contain a limited number of functional groups including acids, amides, alcohols, basic amines and thiols. Is this the ideal number or would additional amino acids allow the generation of proteins or even entire organisms with enhanced properties?...
...To this end, we have developed a methodology that allows one to genetically encode novel amino acids, beyond the common twenty, in both prokaryotic and eukaryotic organisms."
See also:
https://en.wikipedia.org/wiki/Expanded_genetic_code
https://en.wikipedia.org/wiki/Peter_G._Schultz
"This is accomplished by screening libraries of mutant amino acyl tRNA synthetases for mutants which charge nonsense-codon tRNAs with the desired unnatural amino acid. The organism which expresses such a synthetase can then be genetically programmed to incorporate the unnatural amino acid into a desired protein in the usual way, with the nonsense codon now coding for the unnatural amino acid...
More than seventy unnatural amino acids have been genetically encoded in bacteria, yeast, and mammalian cells, including photoreactive, chemically reactive, fluorescent, spin-active, sulfated, pre-phosphorylated, and metal-binding amino acids. This technology allows chemists to probe, and change, the properties of proteins, in vitro or in vivo, by directing novel, lab-synthesized chemical moieties specifically into any chosen site of any protein of interest."
Don't be surprised if you see this work winning a Nobel prize sometime in the future.
