Protein structures have been discovered that may have given rise to life on Earth
The question of the origin of life on Earth has not yet been fully answered, but science is getting closer and closer to the answer; New research has revealed the structures of proteins that may have produced life.
The authors of the new study decided to start with the premise that the form of life known to us depends on the collection and use of energy. In the ancient Earth’s primitive “sauce”, this energy was most likely to come either from the sky, in the form of solar radiation, or from the depths of the earth itself, in the form of heat emanating from hydrothermal vents at the bottom of the ancient seas.
Using this energy at the molecular level means transferring electrons, a fundamental chemical process that involves moving electrons from one atom to another. Electron transfer is a key part of oxidation-reduction reactions that are vital to some of the basic functions of life.
Since metals are the best elements for electron transfer, and complex molecules known as proteins control most biological processes, scientists have decided to combine the two to find proteins that bind to metals.
A methodical, computational approach was used to compare metal-finding proteins and to identify some common characteristics that matched all of them – regardless of the functionality of the protein, the metal to which it is attached, or the organism involved.
“We have seen that the nuclei that bind existing proteins to metals are really similar regardless of whether the proteins themselves are similar. We have also seen that these nuclei connecting to metal are often composed of repetitive substructures, similar to Lego blocks. “Interestingly, we also found these blocks in other regions of the protein, not just metal-bound nuclei and many other proteins that we did not consider in our study,” said Jana Bromberg, a microbiologist at Rutgers University.
The researchers suggested that these common features may well have been present and worked in even the earliest proteins, changing over time and becoming what they are today, but retaining some common structures.
The assumption is that the soluble metals in the archaic ocean that covered the Earth thousands of millions of years ago could be used for the movements of electrons needed to transmit energy and, in turn, for biological life.
“Our observations indicate that rearrangements of these small building blocks may have had one or more common ancestors and produced a number of proteins and their functions that are currently available; “Or life as we know it,” said Bromberg.
In particular, a team of researchers has been able to detect evolutions in the folds of proteins – the forms that proteins take when they become biologically active – that can produce proteins known to us today, much like a molecular tree project.
The research also concludes that biologically functional peptides, or smaller versions of proteins, may have preceded the earliest proteins in time, which are 3.8 billion years old. All this further fills our notion of the origin of life.
As always, any analysis of the origins of life on Earth can be important in finding life on other planets, where life may have begun and evolved in similar biological ways.
“We know very little about the origin of life on this planet, and our research contributes to a better understanding of the hitherto unexplained. “This explanation could also contribute to the search for life on other planets and planetary bodies.”