The only “life” references we have are the types we are familiar with on Earth. Astrobiologists believe that searching for extraterrestrial life, and perhaps the beginnings of life on Earth, will need a larger approach. A NASA-funded group of scientists is working on techniques to anticipate the characteristics of life as we know it. The team discovers universal patterns in life chemistry that do not seem to be dependent on individual molecules in a new research published in the Proceedings of the National Academy of Sciences.
“We want new methods for recognizing and even forecasting elements of life as we don’t know it,” says Sara Imari Walker (Arizona State University), a co-author on the work at the Santa Fe Institute. “In order to do so, we want to figure out what universal rules should apply to every biological system. This entails creating a quantitative explanation for the beginnings of life and guiding our hunt for life on other planets using theory and statistics.”
The interaction of hundreds of chemical substances and processes on Earth gives rise to life. Some of these substances and reactions are prevalent in all living things on the planet. The scientists analyzed enzymes — the functional drivers of biochemistry — found in bacteria, archaea, and eukarya using the Integrated Microbial Genomes and Microbiomes database to show a new sort of biochemical universality.
Enzymes are classified into broad functional types based on their functions, which range from breaking chemical bonds with water molecules (hydrolases) to altering molecular structures (isomerases) to connecting big molecules together (ligases) (ligases). The researchers looked at how the abundance of enzymes in each of these functional categories evolved through time in proportion to the total number of enzymes in an organism. They uncovered a variety of scaling rules — virtually algorithmic correlations — between the number of enzymes in different enzyme classes and the genomic size of an organism. They also discovered that these regulations are independent of the enzymes in those classes.
“We can get these scaling correlations without preserving precise membership in this case. A certain number of transferases is required, but not specific transferases “Professor Chris Kempes of SFI is a co-author on the article. “There are numerous’synonyms,’ and those synonyms scale in predictable ways.”
Organisms on Earth utilize DNA to make proteins, which they do via the usage of RNA. Will the macromolecules of DNA, RNA, and proteins, on the other hand, aid in the identification of life across the cosmos, the understanding of the beginnings of life on Earth, or the development of synthetic biology? “As a group, we don’t believe that’s probable,” Kempes adds. However, the roles of those macromolecules and the metabolic scaling relationships seen in organic, Earth-based life may be. “Even if life elsewhere employed completely different molecules,” Kempes argues, “these functional categories and scaling rules may be preserved across the cosmos.”
First author Dylan Gagler (New York University Langone Health); Hyunju Kim, Bradley Karas, John Malloy, and Veronica Mierzejewski (Arizona State University); and Aaron Goldman (New York University Langone Health) (Oberlin College and the Blue Marble Space Institute for Science).