- 3215 - LIFE - how to get from chemistry to biology? A team of chemists from the Scripps Research Institute reported , November 6, 2020, that they identified a single, primitive enzyme that could have reacted with early Earth catalysts to produce some of the key precursors to life. These short chains of amino acids that power cells, the lipids that form cell walls, and the strands of nucleotides that store genetic information
------------------ 3215 - LIFE - how to get from chemistry to biology?
- Four billion years ago was a little before my time. I can barely remember it. I remember the Earth was covered in a watery sludge swarming with primordial molecules, gases, and minerals. But there was nothing there that the biologists or I would recognize as alive.
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- Then somehow, out of that prebiotic stew emerged the first critical building blocks for life. There emerged proteins, sugars, amino acids, cell walls that would combine over the next billion years to form the first specks of life on the planet.
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- Today’s chemists can synthesize simple molecules that may have existed billions of years ago and test if these ancient enzymes had the skills to turn prebiotic raw material into the stuff of life.
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- For a number of years, Scripp chemists have been experimenting with a synthetic enzyme called diamidophosphate (DAP) that’s been shown to drive a critical chemical process called phosphorylation. Without phosphorylation, which is simply the process of adding a phosphate molecule to another molecule, life wouldn't exist.
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- Your RNA, DNA, and a lot of your biomolecules are phosphorylated. So are sugars, amino acids, and proteins. The enzymes that trigger phosphorylation are called kinases.
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-Kinases use phosphorylation to send signals instructing cells to divide, to make more of one protein than another, to tell DNA strands to separate, or RNA to form. DAP may have been one of the first primordial kinases to trigger the phosphorylation.
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- By simulating early Earth conditions in the lab, using both a water base and a muddy paste set to varying pH levels. Scientists combined DAP with different concentrations of magnesium, zinc, and a compound called “imidazole” that acted as a catalyst to speed the reactions, which still took weeks or sometimes months to complete.
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- DAP had to successfully trigger phosphorylation events that resulted in simple nucleotides, peptides, and cell wall structures under similar conditions. Past candidates for origin-of-life enzymes could only phosphorylate certain structures under wildly different chemical and environmental conditions. However, phosphorylating could produce the four nucleoside building blocks of RNA, then short RNA-like strands, then fatty acids, lipids, and peptide chains.
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- Does that mean that DAP is the pixie dust that transformed random matter into life?
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- DAP removes a molecule of ammonia instead of water. Phosphate-rich lava flows may have reacted with ammonia in the air to create DAP, or it could have been leached out of phosphate-containing minerals. Or maybe it even arrived on the back of a meteorite forged by a far-off star.
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- One thing is clear, without DAP or something like it, Earth might still be a lifeless mud puddle.
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- July 6, 2021 LIFE - how to get from chemistry to biology? 3214
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