Much like language, proteins form meaning through the arrangement of their basic building blocks. Now, scientists from the Max Planck Society have reconstructed primordial protein building blocks using comparative studies of modern proteins by taking advantage of computational methods. Through this analysis, they discovered 40 ancestral peptidic protein fragments that may be remnants from the time when proteins were first created 3.5 billion years ago.
From bacteria to humans, proteins are the essential building blocks to all forms of life - in our bodies, they are necessary for numerous chemical processes such as digestion and protection from viruses and they form our hair, bones and muscles.
"Life can be viewed as substantially resulting from the chemical activity of proteins," Andrei Lupas, who headed the research, said in a news release.
Lupas and his team of researchers are interested in understanding the origination of proteins and uncovering their ancient history. Today, we know that these complex biomolecules are typically built through the assembly of just a few thousand core units, which are referred to as domains. However, it is still not clear how these units emerged.
The researchers investigated the possibility that the first protein domains came to be through fusion and incremental growth from an ancient set of simple peptides that originated 3.5 billion years ago in an RNA-based pre-cellular life. They tested this hypothesis using a systemic analysis of modern proteins and identified 40 peptidic fragments that occur in proteins that are seemingly unrelated despite their uncanny similarities in structure and sequence.
The scientists concluded that these fragments are the remnants of an ancient RNA-peptide world, which is what preceded the DNA-based life that we now know today. Future studies will need to examine these fragments experimentally in order to determine just how much they contribute to the formation of protein structure.
"If we elucidate this process, we should be able to create new protein forms," Lupas said.
The findings were published in the Dec. 14 issue of eLife.
