Abiogenesis is the gap creationists prefer to shoehorn their ever-shrinking little god into because they feel safer placing it there, believing that they have an unarguable claim that 'you can't get life from non-life'. Hilariously, you can sow confusion in their smug certainty in two simple ways:
- Ask them to define 'life' and state whether it is a substance, a process or something else, because it only takes a moment's thought to realise 'life' is what we call the metabolic processes that organic molecules perform, so is simply the laws of chemistry and physics in operation. There is no magic ingredient needed.
- Ask them what happens when the non-living food they eat becomes living tissues during the processes of digestion and assimilation if it is 'impossible'?
There is nothing in the laws of chemistry or physics that makes abiogenesis impossible; given the right conditions there is no reason the inorganic chemicals present on the early Earth couldn't build more complex molecules or why those molecules couldn't perform the necessary processes to grow, repair and replicate. And once replication is possible, then selection would have been inevitable, and with selection, the processes which performed best would inevitably produce more copies.
Of course this can't be replicated easily in a laboratory because what no laboratory process can replicate is the long period of time, possibly millions of years, the process had on the early Earth, but what scientists can do is show that essential molecules to kick-start the processes could have arisen on the early Earth in the conditions that pertained then.
This is exactly what a team from University College London have shown in respect of a molecule which is the functional unit of one of the basic enzymes involved - Coenzyme A. The molecule is pantetheine. In earlier studies, pantetheine failed to be produced leading some to think that it would not have formed on early Earth and would therefore be absent and unable to play its essential role in metabolism.
Molecular structure of pantetheine
Tell me all about the molecule pantetheine and its role in metabolism; how would its absence on early Earth have made abiogenesis difficult? Pantetheine is a small molecule derived from pantothenic acid (vitamin B5) and cysteamine. Its structure includes a diphosphate group, a cysteamine residue, and a beta-alanine residue. Pantetheine plays a crucial role in metabolism as a component of coenzyme A (CoA), which is an essential cofactor in numerous biochemical reactions, particularly those involved in the synthesis and breakdown of fatty acids, as well as the metabolism of carbohydrates and proteins. Here's a breakdown of its roles:How the UCL team showed how the formation of pantetheine was possible is the subject of a paper in Science. It is also explained in a UCL news release:Now, regarding the role of pantetheine in abiogenesis: Abiogenesis refers to the natural process by which life arises from non-living matter. On early Earth, before the emergence of life, chemical reactions in primordial environments would have been crucial for the formation of organic compounds, including those necessary for life. Coenzyme A, with its constituent pantetheine, is essential for many of these reactions.
- Fatty Acid Metabolism: Coenzyme A, containing pantetheine, is necessary for the synthesis and breakdown of fatty acids. During fatty acid synthesis, CoA carries the growing fatty acid chain, while during fatty acid oxidation (beta-oxidation), CoA helps in breaking down fatty acids to generate energy.
- Energy Production: CoA is also involved in the citric acid cycle (Krebs cycle) and oxidative phosphorylation, central processes in cellular energy production. It helps in the conversion of pyruvate to acetyl-CoA, which then enters the citric acid cycle to produce energy-rich molecules.
- Acylation Reactions: Coenzyme A plays a role in acylation reactions, where it transfers acyl groups to various molecules, including proteins and sugars, affecting their activity and function.
The absence of pantetheine, and consequently Coenzyme A, on early Earth would have hindered the formation of complex organic molecules necessary for life. Without the ability to efficiently synthesize fatty acids and derive energy from metabolic pathways, the emergence of life would have been significantly more challenging. Therefore, the presence of molecules like pantetheine likely played a critical role in facilitating the transition from non-living to living matter during abiogenesis.
- Fatty Acid Synthesis: Fatty acids are crucial components of cell membranes and play roles in energy storage. Without the ability to synthesize fatty acids, early life forms would have been unable to create the lipid bilayers necessary for cellular structure.
- Energy Metabolism: The ability to generate and utilize energy is fundamental to life. Coenzyme A's involvement in energy production pathways such as the citric acid cycle and fatty acid oxidation would have been necessary for the metabolism of early organisms, allowing them to derive energy from available nutrients.
- Biosynthesis of Essential Molecules: Coenzyme A is also involved in the biosynthesis of various essential molecules besides fatty acids, including sterols, isoprenoids, and neurotransmitters. These molecules are crucial for cellular structure, signaling, and function.
The compound, pantetheine, is the active fragment of Coenzyme A. It is important for metabolism - the chemical processes that maintain life. Earlier studies failed to synthesise pantetheine effectively, leading to suggestions that it was absent at life’s origin.Technical detail is provided in the team's aper in Science which sadly is copyright protected, so only the Abstract can be posted here:
In the new study, published in the journal Science, the research team created the compound in water at room temperature using molecules formed from hydrogen cyanide, which was likely abundant on early Earth.
Once formed, the researchers said, it is simple to envisage how pantetheine might have aided chemical reactions that led from simple forerunners of protein and RNA molecules to the first living organisms – a moment that is thought to have occurred 4 billion years ago.
The study challenges the view among some researchers in the field that water is too destructive for life to originate in it and that life more likely originated in pools that periodically dried out.
Driving the reactions that produced pantetheine were energy-rich molecules called aminonitriles, which are closely chemically related to amino acids, the building blocks of proteins and of life.
Members of the same team, led by Professor Matthew Powner (UCL Chemistry), have already used similar chemistry powered by aminonitriles to demonstrate how other key biological ingredients could be created at the origin of life, including peptides (protein-creating chains of amino acids) and nucleotides (the building blocks of RNA and DNA).
A notable earlier attempt to synthesise pantetheine was made in 1995 by the late American chemist Stanley Miller, who had started the field of origin of life experiments three decades earlier, creating amino acids from four simple chemicals in glass tubes.This new study is further evidence that the basic structures of biology, the primary molecules that biology is built from, are predisposed to form through nitrile chemistry. The ease with which different classes of biological molecules can be made using nitriles has convinced me that, rather than life being preceded by one molecule such as RNA, and there being an ‘RNA world’ before life began, the basic molecules of biology emerged alongside each other – a network of RNAs, proteins, enzymes and cofactors leading to the first living organisms.
Our future work will look at how these molecules came together, how pantetheine chemistry talks to RNA, peptide and lipid chemistry for instance, to deliver chemistry that the individual classes of molecule could not deliver in isolation.
Professor Matthew W. Powner, senior author
Department of Chemistry
University College London, London, UK.
However, in the later 1995 experiment, the yields of pantetheine were very low and required extremely high concentrations of chemicals that had been dried out and sealed in an airtight tube before they were heated to 100 degrees Centigrade.
The major difference between Miller’s study and ours is whereas Miller tried to use acid chemistry, we used nitriles. It’s the nitriles that bring the energy and the selectivity. Our reactions just run in water and produce high yields of pantetheine with relatively low concentrations of chemicals needed.
Dr Jasper Fairchild, co-lead author Department of Chemistry
University College London, London, UK.While the paper focuses solely on the chemistry, the research team said that the reactions they demonstrated could plausibly have taken place in pools or lakes of water on the early Earth (but not likely in the oceans as the concentrations of the chemicals would likely be too diluted).It had been assumed you should make these molecules from acids, because using acids appears to be biological, and that is what we are taught at school and at university. We are taught peptides are made from amino acids. Our work suggests this conventional view has ignored an essential ingredient, the energy required to forge new bonds. The reactions look a little different with nitriles but the end products – the basic units of biology – are indistinguishable whether formed through acid or nitrile chemistry.
Professor Matthew W. Powner
Because pantetheine looks so unusual and complex, it has always been thought that its creation must have come after the advent of complex life, but our work suggests this molecule has always been there, and if so, it certainly would have contributed to the beginning of life on this planet. This paper goes to show that just because the structure of a molecule looks complex, it doesn’t mean the chemistry that generated it needs to be as well.
Dr Saidul Islam, co-lead author
Department of Chemistry
University College London, London, UK.
AbstractWhat we can now expect is for creationists to try to spring what they think is a prepared gotcha! for when someone shows how abiogenesis is possible based on the evidence of laboratory experiments: that this proves intelligence must have been involved (so showing that their constant demands for science to produce 'life' in a laboratory are disingenuous.
Coenzyme A (CoA) is essential to all life on Earth, and its functional subunit, pantetheine, is important in many origin-of-life scenarios, but how pantetheine emerged on the early Earth remains a mystery. Earlier attempts to selectively synthesize pantetheine failed, leading to suggestions that “simpler” thiols must have preceded pantetheine at the origin of life. In this work, we report high-yielding and selective prebiotic syntheses of pantetheine in water. Chemoselective multicomponent aldol, iminolactone, and aminonitrile reactions delivered spontaneous differentiation of pantoic acid and proteinogenic amino acid syntheses, as well as the dihydroxyl, gem-dimethyl, and β-alanine-amide moieties of pantetheine in dilute water. Our results are consistent with a role for canonical pantetheine at the outset of life on Earth.
Fairchild, Jasper; Islam, Saidul; Singh, Jyoti; Bučar, Dejan-Krešimir; Powner, Matthew W.
Prebiotically plausible chemoselective pantetheine synthesis in water
Science 383 6685; 911-918. DOI: 10.1126/science.adk4432
© 2024 The authors/American Association for the Advancement of Science.
Reprinted with kind permission under license #5735580156082
This is also a nonsensical parrot squawk of course, because what the scientists do is simply create the conditions in which the laws of chemistry and physics work to produce the molecules from which life was built, so showing that natural processes alone were sufficient to produce abiogenesis.
According to creationism, special god-magic is required to make chemicals react to form more complex molecules; it isn't enough to just have the right conditions. As childlike teleological thinkers, they find it hard to understand how atoms 'know' how to join with other atoms in the right way, unless a sentient agent tells them. In their world, all things, even fundamental particles, are sentient, because, to a toddler, that's the way the world seems to work.
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