RNA(tC19Z)/creation of biological life II
The gas nebulas in our universe are filled with glucose (C6H12O6) which is the ingredient for RNA end DNA, the building blocks of life, together with proteins. Glucose forms ribose in those gas nebulas. This process forms the spine of RNA. The synthesised tC19Z-enzym mirrors the image of the primitive cellular structure of young earth. (An enzym is a biological catalyst that can accelerate certain chemical reactions.)
The tC19Z-enzym, created in the MRC Laboratory of Molecular Biology in Cambridge, can be an artificial version of the enzymes of the early earth and an indication of how life itself began. It functions as a self-replicator. The synthetic enzym can also reliably copy RNA sequences up to 95 lettres long. The crucial part is that tC19Z can copy pieces of RNA, who are half as long (48%), as itself. tC19Z is closing in on that goal.
tC19Z could be able to surround itself with additional molecular apparatus which means the launch of the evolution of a more complex life.
Earths primordial soup was composed by hydrogen sulfide, methane, nitrogen and steam. These ingredients formed the base for the self-replicant RNA. Protein always needs to be formed by 400 left-turning amino acids to be able to form a building block for life.
RNA enzymes have been developed that catalyze the RNA-templated polymerization of RNA utilizing nucleoside triphosphate (NTP) substrates. These enzymes accurately copy certain RNA sequences up to 95 nucleotides in length. and when made to operate at near-freezing temperatures for 7 days, can generate products up to 206 nucleotides in length.
A somewhat different approach relies on RNA enzymes with RNA-templated RNA ligase activity to join oligonucleotide substrates to form complementary RNA products. It has been proposed that the first replicating, evolving systems on Earth operated by this mechanism and only later came to depend upon residue-by-residue polymerization.
An RNA ligase enzyme has been developed that catalyzes the production of additional copies of itself through the joining of two component oligonucleotide substrates.
To enable the propagation of genetic information, the self-replicating RNA ligase has been converted to a cross-replication format whereby two RNA enzymes catalyze each other’s synthesis from a total of four component substrates.
Recombination can occur, resulting in novel variants that compete for utilization of the oligonucleotide substrates. Those variants that have faster exponential growth rates enjoy a selective advantage, resulting in the self-sustained Darwinian evolution of the fittest replicators.
The self- and cross-replicating RNA enzymes are the only known informational macromolecules that bring about their own exponential amplification. They can do so indefinitely, so long as an ongoing supply of substrates is made available. At a constant temperature of 44°C, the exponential growth rate of the replicating enzymes is 0.03 min−1, corresponding to a doubling time of 20 min (Ferretti and Joyce, 2013). Amplification can be made dependent on recognition of a target ligand by appending a ligand-binding domain (aptamer) to the catalytic domain of the enzyme.
A previous study demonstrated that if it were possible to increase the catalytic efficiency of the replicating enzymes without causing product dissociation to become rate limiting, the exponential growth rate could be increased by several-fold, resulting in a doubling time of less than 5 min.
RNA enzymes can be polymerized in water solution in presence of clay minerals in a specialized laboratory.
Table of highly Efficient Self-Replicating RNA Enzymes:
Round,Format,Enzyme (pmol),Substrate (nM),Time (min) 1, A, 830, 250, 60
2, A, 200, 100, 5
3, A, 100, 50, 2.5
4, B, 10, 2, 0.5
5, B, 10, 2, 0.5
6, A, 25, 50, 1
7, A, 25, 50, 1
8, A, 25, 25, 0.5
9, A, 5, 5, 0.08
10, A, 5, 5, 0.08
RNA nucleosides are formed out of adenine, guanine, cytosine and uracil bases which are linked to ribose sugar.
Nucleosides have to bind a phosphate group or have to be phosphorylated at their 5' carbon to convert them into nucleotides.
Phosphates can be obtained by volcanically produced linear polyphosphates or from their breakdown products.
The above is only possible in presence of urea, ammonium chloride and heat in a specialized laboratory.
Een eiwit producerende machine. De zwarte ketens RNA brengen het juiste aminozuur (bolletje) bij een codon van de groene keten. De gele keten koppelt de bolletjes aan elkaar. Nadien laten de losse zwarte ketens weer los.
