Theoretical origin of life: easy lab manipulations (Introduction)

by David Turell @, Monday, April 25, 2016, 17:50 (1371 days ago) @ David Turell

Here we go again. come up with some proteins, not known to be on early Earth, do some lab playing and we get RNA-like molecules, not RNA itself, but close enough to imagine whatever:

"Using two molecules known as barbituric acid and melamine, the researchers formed proto-nucleotides so strongly resembling two of RNA's nucleotides that it is tempting to speculate that they are indeed their ancestors.

"The two ingredients would have been readily abundant for reactions on a prebiotic Earth, Hud said. "And they would have been well suited for primitive information coding," he added.

"Because of the resemblances and properties, some scientists already have speculated on an ancestral role for melamine and barbituric acid.


"To claim ancestry, we would have to show a mechanism by which these nucleotides we made in the lab could turn into the existing nucleotides in RNA," said Ram Krishnamurthy, Hud's collaborator from the Scripps Research Institute in La Jolla, California. "It's a complex path that we'd have to at least design on paper, and we're not there."


"First, they occurred quickly and the resulting nucleotides spontaneously paired with each other in water, forming hydrogen bonds like the Watson-Crick base pairs that create the "ladder-rung" pattern inside RNA and DNA helixes.

"Then the monomers formed long, supramolecular assemblages that look like strands of RNA when viewed with a high resolution microscope.

"There has been no reported chemical reaction so far that has produced existing components of RNA under commonplace circumstances that spontaneously form Crick-Watson pairs in water.


"There was one small caveat.

"'The reaction does not work as well if barbituric acid and melamine are present in the same solution before reacting with ribose because their strong attraction for each other can cause them to precipitate," Hud said. So, the scientists completed the reaction involving barbituric acid separately from the one involving melamine.

"But that should not have proven prohibitive on prebiotic Earth. Barbituric acid and melamine nucleotides could have been formed in separate locations, even in the same pond. And they could have very well been plentiful.

(Comment: Very hopeful. How did they get together?):

"If melamine and barbituric acid formed their respective nucleotides (C-BMP for barbituric acid and MMP for melamine) in separate puddles on the early Earth, then rain could have easily washed the components together, where they would have rapidly assembled into what could have been a precursor to proto-RNA.

"'The question is: Can these self-assemblies make the transition into what makes up life today," Krishnamurthy said.

(Comment: saved by rain)

"The chemical reactions that produce the barbituric acid and melamine nucleotides don't require the use of enzymes and extreme parameters like high heat and pressure. Reminiscent of click chemistry, they could contribute to safe, cost-effective and abundant industrial production."

Comment: final 'save', no enzymes needed! Intelligent design magic.

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