How calcium may have unlocked the origins of the molecular asymmetry of life

A new study led by researchers at the Institute of Life Sciences of the Earth (ELSI) at the Institute of Sciences, Tokyo, has discovered a surprising role for calcium in the configuration of the first molecular structures of life. Their findings suggest that calcium ions can selectively influence how primitive polymers are formed, shedding light on a long -standing mystery: how the molecules of life came to prefer a single “hand” (chirality).

The study is published in Proceedings of the National Academy of Sciences.

Like our left and right hands, there are many molecules in two forms of mirror image. However, life on Earth has a surprising preference: DNA sugars are right -handed, while proteins are built from left -handed amino acids. This phenomenon, called homoquirality, is essential for life as we know it, but how it emerged for the first time remains a great puzzle in the investigation of origins of life.

The team investigated tartaric acid (TA), a simple molecule with two chiral centers, to explore how the early earth’s environment could have influenced the formation of homoquirales polymers. They discovered that calcium dramatically alters how TA molecules bind.

Without calcium, the pure left or right is easily polymerized in polyesters, but the mixtures that contain equal amounts in both forms do not easily form polymers. However, in the presence of calcium, this pattern is reversed: Calcium slows the polymerization of pure ta while allowing mixed solutions to polymerize.

“This suggests that the availability of calcium could have created environments in the early land where homociral polymers were favored or disadvantaged,” says Chen Chen, a special postdoctoral researcher at the Riken center for sustainable science of resources (CSRS), which directed the study.

The researchers propose that calcium drives this effect through two mechanisms: first, by joining TA to form calcium tartrato crystals, which selectively eliminate equal amounts of left and right molecules of the solution; and second, altering the polymerization chemistry of the remaining TA molecules. This process could have amplified small imbalances in chirality, which ultimately leads to the uniform hand observed in modern biomolecules.

What makes this study especially intriguing is its suggestion that polyesters, simple polymers formed from molecules such as tartaric acid could have been among the first homociraral molecules of life, even before RNA, DNA or proteins.

“The origin of life is often discussed in terms of biomolecules such as nucleic acids and amino acids,” explains the specially designated associated professor at Elsi, Tony Z. Jia, who co-drew the study. “However, our work introduces an alternative perspective: that ‘non -biomolecules’ such as polyesters may have played a fundamental role in the first steps towards life.”

The findings also highlight how the different environments in the early earth could have influenced what types of polymers they formed. Poor configurations in calcium, such as some lakes or ponds, may have promoted homoquirales polymers, while calcium -rich environments could have favored mixed chiral polymers.

Beyond chemistry, this research joins multiple scientific fields (biophysics, geology and material science) to explore how simple molecules interact in dynamic prebiotic environments. The study is also the result of years of interdisciplinary collaboration, which brings together researchers from seven countries in Asia, Europe, Australia and North America.

“We face significant challenges in the integration of all complex chemical, biophysical and physical analysis in a clear and logical way,” says the co-leader of the Ruiqin Yi project of the Institute of Geochemistry of Guangzhou, Academy of Sciences of China.

“But thanks to the hard work and dedication of our team, we have discovered a new convincing piece of the origins of life.”

This research not only deepens our understanding of the beginnings of life on earth, but also suggests that similar processes could be at stake on other planets, helping scientists seek life beyond our world.