Lengthy article. Worth a skim.
https://phys.org/news/2024-08-life-rainwater-protocell-walls.html
One of the major unanswered questions about the
origin of life is how droplets of RNA floating
around the primordial soup turned into the
membrane-protected packets of life we call cells.
A new paper by engineers from the University of
Chicago's Pritzker School of Molecular Engineering
(UChicago PME), the University of Houston's
Chemical Engineering Department, and biologists
from the UChicago Chemistry Department, have
proposed a solution.
In the paper, published in Science Advances,
UChicago PME postdoctoral researcher Aman Agrawal
and his co-authors—including UChicago PME Dean
Emeritus Matthew Tirrell and Nobel Prize-winning
biologist Jack Szostak—show how rainwater could
have helped create a meshy wall around protocells
3.8 billion years ago, a critical step in the
transition from tiny beads of RNA to every
bacterium, plant, animal, and human that ever
lived.
...
https://www.science.org/doi/10.1126/sciadv.adn9657
Did the exposure of coacervate droplets to rain
make them the first stable protocells?
Abstract
Membraneless coacervate microdroplets have long
been proposed as model protocells as they can grow,
divide, and concentrate RNA by natural partitioning.
However, the rapid exchange of RNA between these
compartments, along with their rapid fusion, both
within minutes, means that individual droplets
would be unable to maintain their separate genetic
identities. Hence, Darwinian evolution would not
be possible, and the population would be vulnerable
to collapse due to the rapid spread of parasitic
RNAs. In this study, we show that distilled water,
mimicking rain/freshwater, leads to the formation
of electrostatic crosslinks on the interface of
coacervate droplets that not only suppress droplet
fusion indefinitely but also allow the
spatiotemporal compartmentalization of RNA on a
timescale of days depending on the length and
structure of RNA. We suggest that these nonfusing
membraneless droplets could potentially act as
protocells with the capacity to evolve
compartmentalized ribozymes in prebiotic
environments.
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