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Scaling Laws in Enzymes May Help Predict Strange Alien Life “As We Don’t Know It”

The only references we have for “life” are the forms we know on Earth. Astrobiologists suspect that the search for alien life, and even for the origins of life on Earth, may require a broader scope. A NASAEstablished in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. It's vision is "To discover and expand knowledge for the benefit of humanity."” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>NASA-funded team of researchers is developing tools to predict the features of life as we don’t know it. In a new study published in the Proceedings of the National Academy of Sciences, the team identifies universal patterns in the chemistry of life that do not appear to depend on specific molecules.

“We want to have new tools for identifying and even predicting features of life as we don’t know it,” says SFI External Professor Sara Imari Walker (Arizona State University), a co-author on the paper. “To do so, we are aiming to identify the universal laws that should apply to any biochemical system. This includes developing quantitative theory for the origins of life, and using theory and statistics to guide our search for life on other planets.”

On Earth, life emerges from the interplay of hundreds of chemical compounds and reactions. Some of these compounds and reactions are found universally across Earth’s organisms. Using the Integrated Microbial Genomes and Microbiomes database, the team investigated the enzymes — the functional drivers of biochemistry — found in bacteria, archaea, and eukarya to reveal a new kind of biochemical universality.

Planets Similar to Earth

Researchers discovered various scaling laws between the number of enzymes in different enzyme classes and the size of an organism’s genome. Credit: NASA/Ames/JPL-Caltech

Enzymes can be categorized into a taxonomy of broad functional classes — groups designated by what they do, from using water molecules to break chemical bonds (hydrolases) to rearranging molecular structures (isomerases) to joining large molecules together (ligases). The team compared how the abundance of enzymes in each of these functional categories changed in relation to the overall abundance of enzymes in an organism. They discovered various scaling laws — almost algorithmic relationships — between the number of enzymes in different enzyme classes and the size of an organism’s genome. They also found that these laws don’t depend on the particular enzymes in those classes.

“Here we find that you get these scaling relationships without needing to conserve exact membership. You need a certain number of transferases, but not particular transferases,” says SFI Professor Chris Kempes, a co-author on the paper. “There are a lot ‘synonyms,’ and those synonyms scale in systematic ways.”

On Earth, organisms use DNADNA, or deoxyribonucleic acid, is a molecule composed of two long strands of nucleotides that coil around each other to form a double helix. It is the hereditary material in humans and almost all other organisms that carries genetic instructions for development, functioning, growth, and reproduction. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>DNA and, through RNARibonucleic acid (RNA) is a polymeric molecule similar to DNA that is essential in various biological roles in coding, decoding, regulation and expression of genes. Both are nucleic acids, but unlike DNA, RNA is single-stranded. An RNA strand has a backbone made of alternating sugar (ribose) and phosphate groups. Attached to each sugar is one of four bases—adenine (A), uracil (U), cytosine (C), or guanine (G). Different types of RNA exist in the cell: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA).” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>RNA, create proteins. But will the macromolecules of DNA, RNA, and proteins help us identify life across the universe, understand the origins of life on Earth, or develop synthetic biology? “As a team, we think that’s not likely,” says Kempes. The functions those macromolecules serve, however, and the metabolic scaling relationships observed in organic, Earth-based life, just might be. “Even if life elsewhere used really different molecules, these sort of functional categories and scaling laws might be conserved throughout the universe,” says Kempes.

For more on this research, see New Astrobiology Research Predicts Alien Life “As We Don’t Know It.”

Reference: “Scaling laws in enzyme function reveal a new kind of biochemical universality” by Dylan C. Gagler, Bradley Karas, Christopher P. Kempes, John Malloy, Veronica Mierzejewski, Aaron D. Goldman, Hyunju Kim and Sara I. Walker, 25 February 2022, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2106655119

Additional authors on this study are first author Dylan Gagler (New York UniversityFounded in 1831, New York University (NYU) is a private research university based in New York City.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>New York University Langone Health); Hyunju Kim, Bradley Karas, John Malloy, and Veronica Mierzejewski (Arizona State University); and Aaron Goldman (Oberlin College and the Blue Marble Space Institute for Science).

This work was supported by a grant from the John Templeton Foundation, and the NASA-funded Laboratory for Agnostic Biosignatures and an Interdisciplinary Consortia for Astrobiology Research (ICAR).

Source: SciTechDaily