A Rutgers led study illuminates one of science's most persistent mysteries: How did metabolism – the process through which life strengthens itself by transforming energy from food to movement and growth start?
To answer this question, the researchers reversed a primordial protein and inserted it into a living bacterium, where it successfully operated the cell's metabolism, growth and reproduction, according to the study in Proceedings of the National Academy of Sciences
"We are closer to understanding the inner cell's inner effects, which were the ancestors of all life on earth – and therefore understanding how life originated in the first place and the ways life could have taken on other worlds," says lead author Andrew Mutter, a postdoctoral associate at Rutgers University's Department of Marine and Coastal Sciences.
The discovery also has implications for the field of synthetic biology, which exploits the metabolism of microbes to produce industrial chemicals and bioelectronics, which seek to use the natural circulation of cells for energy storage and other functions.
The researchers looked at a class of proteins called ferredoxins that support metabolism in bacteria, plants and animals by moving electricity through cells. These proteins have different complex forms in today's living things, but scientists speculate that they all originate from a much simpler protein that was present throughout the ancestor of life.
Similar to ways biologists compare modern birds and reptiles with conclusions about their common ancestors, the researchers compared ferredoxin molecules present in living things and using computer models shaped ancestral forms that could have existed at an earlier stage in life's development.
This research led to the creation of a basic version of the protein – a simple ferredoxin that is capable of conducting electricity in a cell and which could have given rise to the many types that exist today over the abilities of evolution. .
Then to prove their model of the old protein could actually support life, they inserted it into a living cell. They took the genome of E. coli bacteria, removed the gene it uses to create ferredoxin in nature, and spliced into a gene for their reverse-engineered protein. The modified E. coli colony survived and grew although slower than normal.
Study co-author Vikas Nanda, professor at Rutgers Robert Wood Johnson Medical School and the Center for Advanced Biotechnology and Medicine, stated the discovery's impact on synthetic biology and bioelectronics comes from the role of ferredoxins in the life cycle.
"These proteins channel electricity as part of a cell's internal circuit. The ferredoxins that occur in modern life are complex – but we have made a removed version that could still build on future experiments simple version for possible industrial applications, "Nanda said.
Scientists identify protein that could have existed when life began
Andrew C. Nut or, "De novo construction of symmetrical ferredoxins containing electrons in vivo," PNAS (2019). www.pnas.org/cgi/doi/10.1073/pnas.1905643116
Scientists identify the origin of the substances (2019, July 1)
July 1, 2019
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