How simple, non-living components may have given rise to primitive life on our planet.

Rutgers-led research has uncovered the structures of proteins that may be responsible for the genesis of life in the primordial soup of old Earth, answering one of biology’s most profoundly unresolved riddles.

The study was published today in the journal Science Advances.

The researchers looked at how simple, non-living components could have given rise to primitive life on our planet. They wondered what characteristics constitute life as we know it, and came to the conclusion that anything living would have needed to collect and consume energy from sources like the Sun or hydrothermal vents.

In molecular terms, this means that the ability to shuffle electrons is essential for life. Because metals (think ordinary electrical lines) are the best materials for electron transmission and proteins are responsible for the majority of biological activity, the researchers chose to investigate the combination of the two — proteins that bind metals.

They analyzed all current protein structures that bind metals to determine whether there were any similar traits, assuming that these shared features existed in ancestral proteins and were diversified and passed down to generate the diverse range of proteins we see today.

Understanding how new folds arose from previously existing ones is important in protein evolution, so the researchers devised a computational method that revealed that the vast majority of currently existing metal-binding proteins are similar, regardless of the type of metal they bind to, the organism from which they came, or the function assigned to the protein as a whole.

“We saw that the metal-binding cores of existing proteins are indeed similar even though the proteins themselves may not be,” says the study’s lead author Yana Bromberg. “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.”

“We have very little information about how life arose on this planet, and our work contributes a previously unavailable explanation,” adds 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.”

Image Credit: RUTGERS

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