Theoretical origin of life; proteins stabilize membranes (Introduction)

by David Turell @, Wednesday, August 14, 2019, 19:05 (6 days ago) @ David Turell

More pie in the sky ignoring Tour's warning essay:

https://www.sciencedaily.com/releases/2019/08/190812155502.htm

"Scientists have discovered that the building blocks of proteins can stabilize cell membranes. This finding may explain how the first cells emerged from the primordial soup billions of years ago: The protein building blocks could have stabilized cell membranes against salt and ions that were present in ancient oceans. In addition, membranes may have been a site for these precursor molecules to co-localize, a potential mechanism to explain what brought together the ingredients for life.

***

"A team of researchers at the University of Washington has solved this puzzle using only molecules that would have been present on the early Earth. Using cell-sized, fluid-filled compartments surrounded by membranes made of fatty acid molecules, the team discovered that amino acids, the building blocks of proteins, can stabilize membranes against magnesium ions. Their results set the stage for the first cells to encode their genetic information in RNA, a molecule related to DNA that requires magnesium for its production, while maintaining the stability of the membrane.

***

"The team hypothesized that amino acids might also stabilize membranes. They used a variety of experimental techniques -- including light microscopy, electron microscopy and spectroscopy -- to test how 10 different amino acids interacted with membranes. Their experiments revealed that certain amino acids bind to membranes and stabilize them. Some amino acids even triggered large structural changes in membranes, such as forming concentric spheres of membranes -- much like layers of an onion.

"'Amino acids were not just protecting vesicles from disruption by magnesium ions, but they also created multilayered vesicles -- like nested membranes," said lead author Caitlin Cornell, a UW doctoral student in the Department of Chemistry.

"The researchers also discovered that amino acids stabilized membranes through changes in concentration. Some scientists have hypothesized that the first cells may have formed within shallow basins that went through cycles of high and low concentrations of amino acids as water evaporated and as new water washed in.

"The new findings that amino acids protect membranes -- as well as prior results showing that RNA building blocks can play a similar role -- indicate that membranes may have been a site for these precursor molecules to co-localize, providing a potential mechanism to explain what brought together the ingredients for life."

comment: A marvelous example of the hype noted by Tour. So proteins can stabilize membranes, ignoring the issue of how did lipid membranes initially form? How did the initial amino acids get to the earth, and only in left-handed form? Space rocks that have landed here contain few of the necessary essential amino acids.


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