Collecting RNA from non-living building blocks without the help of enzymes is real
Many leading scientists of the planet consider the hypothesis of the origin of life on Earth from the “RNA world” to be one of the most fundamental. The basis of the process of emergence and development of life is the transfer of hereditary information, taking into account the changes that have occurred. And chemicals necessary for the synthesis of biological macromolecules could get onto our planet from cosmic expanses with meteorite rain. Until recently, the question of how to synthesize purines, one of the key components of DNA, RNA, and the energy metabolism of any cell, remains unclear in the light of the theory of the RNA world. Scientists at the University of Munich Ludwig – Maximilian managed to synthesize purines in laboratory conditions that were close to those that existed on Earth “at the beginning of time” and at the same time do without the participation of complex enzymes.
Ribonucleic acids are well suited to the role of the original source of life, as they are able to store and copy information, while allowing for neutral, harmful or useful mutations. At the same time, speaking of DNA, we assume that it still needs the help of proteins to copy, while RNA is quite capable of acting as an enzyme and participating in certain chemical reactions. Moreover, RNA molecules are quite capable of increasing the ribonucleotide chain, in other words, RNA is able to synthesize RNA. This is how the picture of the RNA world is built, following which the source of life on Earth was a kind of primary chemical soup, filled with the oldest RNAs that copied themselves.
Like any hypothesis claiming to be true, the described concept has followers and opponents. So, according to one of the objections, reactions involving RNA should not occur in a certain abstract endless primary ocean, but in certain microcells, a kind of microreactors that create lipid membranes. In turn, the creation of such membranes will require proteins that have not existed in those ancient times. Proponents of the concept of the origin of life from RNA argue that according to recent studies, micropores in mineral rocks at the bottom of the ancient ocean could claim the role of such chemical reactors.
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Another question the opponents of the hypothesis of the “RNA world” like to ask: where did the low molecular weight raw material for the RNA polymers come from? As is known, RNA monomers are ribonucleotides with a complex structure synthesized in modern laboratories with the participation of proteins. At some stage a version was expressed that life on our planet arose due to some metal catalysts entering into metabolic reactions at some initial stage. After a while, the consequence of these reactions was the creation of “semi-finished products” for the further synthesis of higher biomolecules.
But, thanks to research, it turned out that the oldest RNAs turned out to be completely independent and able to do without the help of any catalysts. In 2009, John Sutherland of the University of Cambridge, together with his colleagues, published an article stating that a number of bricks for RNA can be made from acetylene and formaldehyde, without the participation of any catalysts. For the reaction to take place in the right direction, it was enough to reproduce the conditions corresponding to the scientific community’s view of the primary “earth soup”.
Last year, on the pages of the Nature Chemistry publication, Sutherland published an article stating that the presence of hydrogen cyanide (HCN), hydrogen sulfide (H2S), and ultraviolet radiation is enough for the synthesis of nucleic acid protokirpikov.
But one cannot fail to note that it was not possible to synthesize “semi-finished products” for RNA from elementary protohistorical materials for all ribonucleotide monomers. As is known, the composition of RNA - compounds contains nitrogenous bases - adenine (A), guanine (G), cytosine (C) and uracil (U) - they are the very genetic letters encoding hereditary information (in DNA all the same , only instead of uracil - thymine (T)). Chemically, they differ, cytosine and uracil belong to pyrimidine bases, adenine and guanine - to purine ones. The synthesis scheme proposed by Sutherland and his group worked for the pyrimidines, but was not suitable for purines or, with repetition of a set of initial conditions for the origin of life, made it possible to obtain an extremely small amount of purines.
The controversy was resolved by Thomas Carell ( Thomas Carell ) and his colleagues at the Ludwig – Maximilian University of Munich, who have been involved in chemical modifications of nucleic acids for many years. At one stage of the research, scientists discovered that one of the pyrimidine modifications is formamidopyrimidine (FaPy), which reacts with DNA and is able to turn into purine bases. It remains only a little to check whether it is possible to reproduce the same reactions, but in “historical” conditions.
An article of May 13, 2016, published in the journal Science and telling about the work of Carrell, notes that purines for RNA can indeed be obtained with only hydrogen, cyanide, and water. However, in order to make the reaction directed and to get exactly those intermediate compounds that could turn into purines, we had to acidify the reaction medium, which in general did not contradict the initial conditions of the experiment. The resulting intermediate product, aminopyrimidine, reacted quite willingly with formic acid or with formamide, and then with sugars, which resulted in a lot of purine bases. Formic acid and formamide were detected last year by the Rosette apparatus on comet 67P / Churyumov-Gerasimenko, which suggests that these reagents could well have been “delivered” to us from the depths of space.
Summing up, we can say that based on the concept proposed by scientists on the basis of the tools found and the results of the experiments, we can conclude: life on planet Earth could well be brought from the expanses of the Universe, and, importantly, not in the form of a magic seed, the simplest bacterium or a finished biological molecule, and in the form of an elementary building chemical raw material. So, for example, the same hydrogen cyanide in high concentrations is present in meteorites, which plentifully poured onto the surface of our planet hundreds of millions of years ago.
In addition to purine and pyrimidine nitrogenous bases, ribose and phosphoric acid should be mentioned as part of ribonucleotides, but they are simpler, and sugar has long been known that they can be completely synthesized in an abiogenic way, even under "star" conditions. Thus, recent studies have significantly and fundamentally complemented the existing concept of the “technology” of the origin of life on the planet and show that this process can be reproduced using elementary chemical raw materials, without the need for complex enzymes.
True, an equally crucial question remains: how , and most importantly, why did the first RNAs suddenly appear at all, why did the ribonucleotide building blocks of monomers with the familiar letters A, G, C, and U begin to unite, even assuming that all of them were in the same place at the same time ??
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Ribonucleic acids are well suited to the role of the original source of life, as they are able to store and copy information, while allowing for neutral, harmful or useful mutations. At the same time, speaking of DNA, we assume that it still needs the help of proteins to copy, while RNA is quite capable of acting as an enzyme and participating in certain chemical reactions. Moreover, RNA molecules are quite capable of increasing the ribonucleotide chain, in other words, RNA is able to synthesize RNA. This is how the picture of the RNA world is built, following which the source of life on Earth was a kind of primary chemical soup, filled with the oldest RNAs that copied themselves.
Like any hypothesis claiming to be true, the described concept has followers and opponents. So, according to one of the objections, reactions involving RNA should not occur in a certain abstract endless primary ocean, but in certain microcells, a kind of microreactors that create lipid membranes. In turn, the creation of such membranes will require proteins that have not existed in those ancient times. Proponents of the concept of the origin of life from RNA argue that according to recent studies, micropores in mineral rocks at the bottom of the ancient ocean could claim the role of such chemical reactors.
')
Another question the opponents of the hypothesis of the “RNA world” like to ask: where did the low molecular weight raw material for the RNA polymers come from? As is known, RNA monomers are ribonucleotides with a complex structure synthesized in modern laboratories with the participation of proteins. At some stage a version was expressed that life on our planet arose due to some metal catalysts entering into metabolic reactions at some initial stage. After a while, the consequence of these reactions was the creation of “semi-finished products” for the further synthesis of higher biomolecules.
But, thanks to research, it turned out that the oldest RNAs turned out to be completely independent and able to do without the help of any catalysts. In 2009, John Sutherland of the University of Cambridge, together with his colleagues, published an article stating that a number of bricks for RNA can be made from acetylene and formaldehyde, without the participation of any catalysts. For the reaction to take place in the right direction, it was enough to reproduce the conditions corresponding to the scientific community’s view of the primary “earth soup”.
Last year, on the pages of the Nature Chemistry publication, Sutherland published an article stating that the presence of hydrogen cyanide (HCN), hydrogen sulfide (H2S), and ultraviolet radiation is enough for the synthesis of nucleic acid protokirpikov.
But one cannot fail to note that it was not possible to synthesize “semi-finished products” for RNA from elementary protohistorical materials for all ribonucleotide monomers. As is known, the composition of RNA - compounds contains nitrogenous bases - adenine (A), guanine (G), cytosine (C) and uracil (U) - they are the very genetic letters encoding hereditary information (in DNA all the same , only instead of uracil - thymine (T)). Chemically, they differ, cytosine and uracil belong to pyrimidine bases, adenine and guanine - to purine ones. The synthesis scheme proposed by Sutherland and his group worked for the pyrimidines, but was not suitable for purines or, with repetition of a set of initial conditions for the origin of life, made it possible to obtain an extremely small amount of purines.
The controversy was resolved by Thomas Carell ( Thomas Carell ) and his colleagues at the Ludwig – Maximilian University of Munich, who have been involved in chemical modifications of nucleic acids for many years. At one stage of the research, scientists discovered that one of the pyrimidine modifications is formamidopyrimidine (FaPy), which reacts with DNA and is able to turn into purine bases. It remains only a little to check whether it is possible to reproduce the same reactions, but in “historical” conditions.
An article of May 13, 2016, published in the journal Science and telling about the work of Carrell, notes that purines for RNA can indeed be obtained with only hydrogen, cyanide, and water. However, in order to make the reaction directed and to get exactly those intermediate compounds that could turn into purines, we had to acidify the reaction medium, which in general did not contradict the initial conditions of the experiment. The resulting intermediate product, aminopyrimidine, reacted quite willingly with formic acid or with formamide, and then with sugars, which resulted in a lot of purine bases. Formic acid and formamide were detected last year by the Rosette apparatus on comet 67P / Churyumov-Gerasimenko, which suggests that these reagents could well have been “delivered” to us from the depths of space.
Summing up, we can say that based on the concept proposed by scientists on the basis of the tools found and the results of the experiments, we can conclude: life on planet Earth could well be brought from the expanses of the Universe, and, importantly, not in the form of a magic seed, the simplest bacterium or a finished biological molecule, and in the form of an elementary building chemical raw material. So, for example, the same hydrogen cyanide in high concentrations is present in meteorites, which plentifully poured onto the surface of our planet hundreds of millions of years ago.
In addition to purine and pyrimidine nitrogenous bases, ribose and phosphoric acid should be mentioned as part of ribonucleotides, but they are simpler, and sugar has long been known that they can be completely synthesized in an abiogenic way, even under "star" conditions. Thus, recent studies have significantly and fundamentally complemented the existing concept of the “technology” of the origin of life on the planet and show that this process can be reproduced using elementary chemical raw materials, without the need for complex enzymes.
True, an equally crucial question remains: how , and most importantly, why did the first RNAs suddenly appear at all, why did the ribonucleotide building blocks of monomers with the familiar letters A, G, C, and U begin to unite, even assuming that all of them were in the same place at the same time ??
That's all, with you there was a simple service for choosing sophisticated Dronk.Ru equipment. Do not forget to subscribe to our blog , there will be many more interesting ...
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Source: https://habr.com/ru/post/394349/
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