University of Tsukuba researchers decode life’s ‘handedness’, a discovery that could impact humanity’s search for extra-terrestrial life.
University of Tsukuba researchers decode life’s ‘handedness’, revealing how amino acids—the building blocks of life—might favour a left twist, a discovery that could impact humanity’s search for extra-terrestrial life.
In an impressive cosmic sleight of hand, a team of researchers from the University of Tsukuba have shed new light on a key puzzle piece in the grand tapestry of life. Their work, centred on the mystery of life’s ‘handedness’, offers compelling evidence that amino acids, essential for life as we know it, may have been born with a specific twist. The researchers’ findings were published in The Journal of Physical Chemistry Letters.
Life’s penchant for ‘handedness’, known as homochirality, is no small quirk. From DNA’s spiralling double helix to the intricate structures of proteins, it hinges on this molecular orientation. The team explored how aminonitriles, precursors to amino acids, might have formed with a consistent left-handed orientation—a significant first step towards understanding how homochirality arose in the evolution of life.
Contrary to prevailing beliefs that homochirality might have been determined by a flip of the cosmic coin, the team’s study revealed that energy efficiency might have been the key driver. Using cutting-edge computational chemistry methods rooted in quantum mechanics, they showed that left-handed aminonitriles tend to be energetically favoured, and thus more likely to form, under certain conditions.
Diving into the cosmic soup, the team suggested that intense circularly polarised light (CPL), common in some corners of the universe, might have been the magic wand. “When aminonitriles interact with right-handed CPL, a positive enantiomeric excess is formed upon photolysis, resulting in an abundance of left-handed amino acids,” added Mitsuo Shoji, lead and corresponding author of the study.
This discovery could prove pivotal in the search for extra-terrestrial life—since the presence of left-handed amino acids might be an indicator of biological processes. Excitingly, thanks to asteroid sample-return missions like Hayabusa2, launched by the Japan Aerospace Exploration Agency in 2014, scientists can now test these theories directly. The mission has already detected at least 23 types of amino acids from the Ryugu asteroid, offering an encouraging sign for future exploration.
The team’s findings also chart a course for further investigations, including studies of other prebiotic molecules related to D-sugars and nucleobases. As well as enriching our understanding of the nuts and bolts of life, this could open new doors in the search for life elsewhere in the cosmos.
In a universe full of mysteries, it’s reassuring to see that the riddle of life’s ‘handedness’ is gradually being solved. With each molecule they decipher, scientists are piecing together a clearer picture of how life could have sprung from the cosmic dust. As we continue to explore the vast cosmos, we might just discover that life, as we understand it, has a broader presence than we ever imagined.