Could Metal-Binding Proteins Have Been the Origin of Life on Earth?

How life developed out of the primordial soup billions of years ago is one of the great mysteries of science, and a new study argues that metal might have been what gave life its first sparks.

A team led by researchers at Rutgers University say in a new study in Science Advances that metal-binding proteins are a likely first-mover in the development of life on this planet since metal is an easy material to use for transferring electrons.

This electron transfer would be key for converting energy from hydrothermal vents or the Sun into a life-sustaining form.

Using computational algorithms to trace the similarities in the protein folds of existing metal-binding proteins, they worked backward to see how those folds evolved to better understand what earlier proteins that might have given rise to life would have looked like.

“We saw that the metal-binding cores of existing proteins are indeed similar even though the proteins themselves may not be,” Yana Bromberg, a professor in the Department of Biochemistry and Microbiology at Rutgers University-New Brunswick and the study's lead author, said in a statement.

“We also saw that these metal-binding cores are often made up of repeated substructures, kind of like LEGO blocks. Curiously, these blocks were also found in other regions of the proteins, not just metal-binding cores, and in many other proteins that were not considered in our study. Our observation suggests that rearrangements of these little building blocks may have had a single or a small number of common ancestors and given rise to the whole range of proteins and their functions that are currently available -- that is, to life as we know it.”

This could be an important step in understanding how life developed from those earliest proteins into living cells that would go on to proliferate into the incredible diversity of life we see around us today.

“We have very little information about how life arose on this planet, and our work contributes a previously unavailable explanation,” said Bromberg. “This explanation could also potentially contribute to our search for life on other planets and planetary bodies. Our finding of the specific structural building blocks is also possibly relevant for synthetic biology efforts, where scientists aim to construct specifically active proteins anew.”