Theoretical origin of life; new fun and games in the lab (Introduction)

by David Turell , Thursday, January 31, 2019, 18:57 (1911 days ago) @ David Turell

More intelligent design in the lab using membraneless globules to contain supplied chemicals which then react in a way mimicking supposed early life:

https://phys.org/news/2019-01-membraneless-protocells-clues-formation-early.html

"Membraneless assemblies of positively- and negatively-charged molecules can bring together RNA molecules in dense liquid droplets, allowing the RNAs to participate in fundamental chemical reactions. These assemblies, called "complex coacervates," also enhance the ability of some RNA molecules themselves to act as enzymes—molecules that drive chemical reactions. They do this by concentrating the RNA enzymes, their substrates, and other molecules required for the reaction. The results of testing and observation of these coacervates provide clues to reconstructing some of the early steps required for the origin of life on Earth in what is referred to as the prebiotic "RNA world."

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"'RNA—or something similar—has been thought of as a key to solving this dilemma," said Raghav R. Poudyal, Simons Origins of Life Postdoctoral Fellow at Penn State and first author of the paper. "RNA molecules carry genetic information, but they can also function as enzymes to catalyze the chemical reactions needed for early life. This fact has led to the notion that life on Earth went through a stage where RNA played an active role in facilitating chemical reactions—"the RNA World"—where self-replicating RNA molecules both carried the genetic information and performed functions that are now generally carried out by proteins."

"Another common feature of life on Earth is that it is compartmentalized in cells, often with an outer membrane, or in smaller compartments inside cells. These compartments ensure that all the components for the chemical reactions of life are in easy reach, but in the prebiotic world the building blocks for RNA—or the RNA enzymes needed to drive the chemical reactions that could lead to life—would probably have been scarce, floating around in the primordial soup.

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"'It was previously known that RNA molecules can assemble and elongate in solutions with high concentrations of magnesium," said Poudyal. "Our work shows that coacervates made from certain materials allow this non-enzymatic template-mediated RNA assembly to occur even in the absence of magnesium."

"The coacervates are composed of positively charged molecules called polyamines and negatively charged polymers which cluster together to form membraneless compartments in a solution. Negatively charged RNA molecules are also attracted to the polyamines in the coacervates.

"Within the coacervates the RNA molecules are as much as 4000 times more concentrated than in the surrounding solution. By concentrating the RNA molecules in the coacervates, RNA enzymes are more likely to find their targets to drive chemical reactions.

"'Although all the polyamines we tested were able to participate in formation of RNA-rich droplets, they differed in their ability to support RNA elongation," said Christine Keating, professor of chemistry at Penn State and a senior author on the paper. "These observations help us understand how the chemical environment within different membraneless compartments can impact RNA reactions."

"'Although we can't look back to see the exact steps taken to form the first life on Earth, coacervates like the ones we can create in the laboratory may have helped by facilitating chemical reactions that otherwise would not have been possible," said Poudyal."

Comment: More waste of fund money. The 'RNA world' is formed in human scientific imagination and work like this creates salaries for some science folks, but proves nothing that helps us truly understand how life might have started. But it must have had a containing wall.