Rutgers team discovers protein catalyst linked to early life on Earth
A team of Rutgers researchers have recently discovered a simple protein catalyst that existed among the first cells and could have served as a reason for early biological reactions.
The finding was published in the Journal of the American Chemical Society, and outlined how the scientists discovered this primordial peptide, or short protein.
Using computer-generated models, researchers found that this peptide contains only two types of amino acids — rather than the estimated 20 amino acids that synthesize millions of different proteins needed for specific body functions — suggesting it could have spontaneously emerged on the early Earth, according to a press release.
The metal cluster at the core of the peptide resembles the structure and chemistry of iron-sulfur minerals that were abundant in early Earth oceans, according to the press release. The peptide can also charge and discharge electrons repeatedly without falling apart.
"Modern proteins called ferredoxins do this, shuttling electrons around the cell to promote metabolism," said senior author Paul G. Falkowski, a professor in the Department of Marine and Coastal Sciences. "A primordial peptide like the one we studied may have served a similar function in the origins of life."
Among the many different kinds of reactions that are necessary for life to exist is a process called electron transfer, where electrons can be removed or added to certain molecules. This transfer is vital in the providing of chemical energy to cells so that they may function, according to research from the National Center for Biotechnology Information.
Since the 1960s, scientists had proposed that ferredoxins that could mediate electron transfer were present at the time that life arose on Earth, according to the Rutgers study. These early catalysts could have evolved into the more complex enzymes observed today.
In the late 1980s and early 1990s, chemist Günter Wächtershäuser considered that life began on iron- and sulfur-containing rocks in the ocean. Wächtershäuser and others predicted that short peptides would have bound metals and served as catalysts of life-producing chemistry, according to the press release.
Using computer models, Rutgers researchers have discovered thousands of proteins and pinpointed what is referred to as the "Legos of life" — four core chemical structures that can be stacked together to build the myriad proteins inside every organism, according to the press release.
“We don’t have a fossil record of what proteins looked like 4 billion years ago, so we have to take what we have today and start walking backwards, trying to imagine what these proteins looked like,” said Vikas Nanda, a professor in the Department of Biochemistry and Molecular Biology to Rutgers Today.