During cellular respiration, energy is captured when phosphate is added to ADP (adenosine diphosphate) to form ATP; The breakdown of this phosphate releases energy for most cellular functions. But building the complex chemical structure of ATP from scratch requires a lot of energy and six separate steps. While compelling models allow for the possibility of de-energized prebiotic ATP scaffolding from already formed ATP, they also suggest that ATP is probably too scarce, at which point another compound may have played a central role in converting ADP to ATP. point in evolution.
According to Lane and colleagues, the most likely candidate is the two-carbon compound acetyl phosphate (AcP). AcP has been shown to phosphorylate ADP to ATP in water in the presence of iron ions, but many questions remain as to whether other small molecules can work the same way, whether AcP is specific to ADP, or if it can instead work the same way as others. Whether the molecules and iron are unique in their ability to catalyze ADP phosphorylation in water.
In their new work, the authors explored all these questions. Based on data and hypotheses about chemical conditions on Earth prior to the emergence of life, they tested the ability of other ions and minerals to catalyze the formation of ATP in water; none were as effective as iron. They then tested a group of other small organic molecules for their ability to phosphorylate ADP; none were as effective as AcP and only one (carbamoyl phosphate) had any significant activity. Finally, they showed that none of the other nucleoside diphosphates accept phosphate from AcP.
“Our results suggest that AcP as a biological phosphorylator is the most likely precursor to ATP, and that the emergence of ATP as the universal energy currency of the cell was not the result of a ‘frozen coincidence,’ but was due to unique interactions,” Lane says. Between ADP and ACP.”
Source: Ferra
