Rutgers researchers have noted the origins of the protein structures responsible for metabolism: simple molecules that powered early life on Earth and served as chemical indicators that NASA may use to search for life on other planets.
Their study, which estimates what the earliest proteins looked like 3.5 billion to 2.5 billion years ago, is featured in the journal Proceedings of the National Academy of Sciences.
The scientists retraced, like many thousand-piece puzzles, the evolution of enzymes from the present to the past. The solution to the puzzle needed two missing pieces, and life on Earth couldn’t exist without them. By developing a network connected by their functions in metabolism, this staff found the missing pieces.
A Rutgers-led group of scientists called Evolution of Nanomachines in Geospheres and Microbial Ancestors (ENIGMA) is researching with NASA subsidies and through membership in the NASA Astrobiology Program.
The Rutgers workforce focused on two protein “folds” that are likely the first structures in early metabolism. They’re a ferredoxin fold that binds iron-sulfur compounds, and a “Rossmann” fold, which binds nucleotides. These are two items of the puzzle that need to match in the evolution of life.
Proteins are chains of amino acids and a chain’s 3-D path in space is called a fold. Ferredoxins are metals present in modern proteins and shuttle electrons around cells to prompt metabolism.
There is evidence the two folds could have shared the same ancestor and, if true, the ancestor could have been the first metabolic protein of life.