Life's First Molecule Was A Protein, Not DNA Or RNA

Discussion in 'Scientific Studies' started by haidut, Nov 16, 2017.

  1. haidut

    haidut Member

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    I posted a few studied in the past that argued for the primal role of RNA (and not DNA) in evolution.
    Not The "selfish Gene"(DNA), But RNA Be The Driver Of Evolution

    The geneticists like to claim that DNA still rules supreme because it was the primordial molecule that started life and its cycle. However, this new study claims it was neither DNA nor RNA that came first but instead simple proteins, which grew and the started to fold in shapes that eventually created RNA and then DNA molecules. The study fits with recent studies I posted on emergence of life being natural and spontaneous event that requires very few factors such as a few basic building blocks (hydrophobic amino acids) found throughout the Universe and favorable medium (i.e. polar substances like water).
    Hey @Such_Saturation I think you will like this study.

    Life's First Molecule Was Protein, Not RNA, New Model Suggests

    "...Most of those elongated polymers merely continue on their way. But a few end up folding, and some even have a hydrophobic patch of their own, just like the original catalyst. When this happens, the folded molecules with landing pads not only continue to form long polymers in greater and greater numbers, but they can also end up constituting what’s called an autocatalytic set, in which foldamers either directly or indirectly catalyze the formation of copies of themselves. Sometimes two or more foldamers can engage in mutual catalysis, by enhancing reactions that form one another. Although such sets are rare, the number of these molecules would grow exponentially and eventually take over the prebiotic soup. “It’s like lighting a match and setting a forest fire,” Dill said." “That’s the whole magic of it,” he added, “the ability of a small event to leverage itself to much bigger events.” And all that’s needed to spark this process are particular sequences of hydrophobic and polar components, which his model can predict. “Dill’s model shows you need only those two properties,” said Peter Schuster, a theoretical chemist and professor emeritus at the University of Vienna. “That’s a beautiful theoretical result.”

    It puts in doubt the vision of the origin of life that is based on the RNA world hypothesis,” said Andrew Pohorille, director of NASA’s Center for Computational Astrobiology and Fundamental Biology. To him and some other scientists, proteins seem like a “more natural starting point” because they are easier to make than nucleic acids. Pohorille posits that the information storage system found in the earliest rudiments of life would have been less advanced than the nucleic acid-based system in modern cells."
     
  2. meatbag

    meatbag Member

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    Awesome timing I was just reading about this, very interesting topic thanks haidut!

    Here's the studies I had found if anyone is interested, was looking for things along what Peat says here (there is literally nothing out there on de Jong lol);

    "Sidney Fox’ mixture of amino acids had spontaneously, and almost immediately, formed little bacteria-like particles, very uniform in size and shape. And when he added amino acids to the watery solution that these were floating in, the things would grow, incorporating amino acids into their structure, and even produced offsprings (they would reach a certain size and a bud would form). In the absence of water, slightly moist, hot amino acids polymerize spontaneously into proteins. And those proteins spontaneously form little bacteria-like particles that brake up. Following the coacervation principle, they are more stable at a certain small size. The proteins that make up those particles can catalyze reactions incorporating new amino acids into new proteins, allowing them to grow. So, in an hour or two, Sidney Fox demonstrated something very much like the origin of life that Operin and Bungenberg de Jong had just postulated as possible; he demonstrated real growing organisms, like things with real proteins, spontaneously synthesized." - R.Peat
    ~Protection And Restoration Of The Nervous System, 2005 Conference

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    "Systematic relationships have long been recognized between the hydrophobicities of amino acids and (i) their tendencies to be located at the exposed surfaces of globular and membrane proteins and (ii) the composition of their triplets in the genetic code. Here, we show that the same coding relationships are compatible with the high temperatures at which life is widely believed to have originated. An accompanying paper reports that these two properties appear to be encoded separately by bases in the acceptor stem and the anticodon of tRNA."
    Temperature dependence of amino acid hydrophobicities
    "The universal genetic code is the earliest point to which we can trace biological inheritance. Earlier work hinted at a relationship between the codon bases and the physical properties of the 20 amino acids that dictate the 3D conformations of proteins in solution. Here, we show that acceptor stems and anticodons, which are at opposite ends of the tRNA molecule, code, respectively, for size and polarity. These two distinct properties of the amino acid side-chains jointly determine their preferred locations in folded proteins. The early appearance of an acceptor stem code based on size, β-branching, and carboxylate groups might have favored the appearance of antiparallel peptides that have been suggested to have a special affinity for RNA."
    tRNA acceptor stem and anticodon bases form independent codes related to protein folding
     
  3. paymanz

    paymanz Member

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    Im interested to know what organism first started to produce co2 on earth and what they consumed as food?!
     
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