Researchers used innovative X-ray spectroscopy to understand how ionized urea molecules may have contributed to the origin of life on Earth, paving the way for advances in nuclear chemistry. Above is a representation of photoionization-induced proton transfer between two urea molecules in an aqueous urea solution. Credit: Ludger Inhester
A new technology has provided novel insights into a long-standing mystery: How did life originate on Earth?
Before life appeared on our planet, in what researchers refer to as the pre-biological state, the atmosphere was less dense. This means that high-energy radiation from space is ubiquitous and ionized molecules. Some hypothesize that small pools of water containing urea—an organic compound essential for building nucleobases—were exposed to this intense radiation and converted to urea reaction products. These serve as the building blocks of life: DNA And RNA.
But to learn more about this process, scientists need to dive further into the ionization and reaction of urea, as well as the mechanism behind the reaction pathways and energy dissipation.
An international consortium consisting of corresponding author Zhang Yin, currently associate professor at Tohoku University’s International Center for Synchrotron Radiation Innovation Smart (SRIS), together with colleagues from the University of Geneva (UNIGE) and ETH Zurich (ETHZ). The University of Hamburg was able to reveal more thanks to an innovative X-ray spectroscopy approach.
The technology, which used a high-harmonic generation light source and a sub-micron liquid flat-jet, enabled researchers to probe chemical reactions occurring in liquids with unmatched temporal precision. Importantly, the groundbreaking approach allowed the researchers to probe complex changes in urea molecules at the femtosecond level, which is a quadrillionth of a second.
„We have shown for the first time how urea molecules behave after ionization,” says Yin. „Ionizing radiation damages the urea biomolecules. But in dissipating the energy from the radiation, the ureas undergo a dynamic process that occurs on the femtosecond time scale.
Previous studies examining molecular reactions were limited to the gas phase. To extrapolate this to the aquatic environment, the natural environment for biochemical processes, the team had to design a device that could create an ultra-thin liquid jet less than one millionth of a meter thick. A void. A thick jet would prevent measurements by absorbing part of the X-rays.
As a leading experimenter, Yin believes there is more to the evolution of life than how it evolved on Earth. It opens a new path in the novel scientific field of atom chemistry. „Short pulses of light are essential for understanding chemical reactions in real time and pushing the boundaries in atomic chemistry. Our approach enables scientists to monitor a molecular movie, following every step of the process.”
Note: „FemdoSegand Proton exchange in urea solution by X-ray spectroscopy” Zhang Yin, Yi-Bing Song, Tadas Balciabhunas, Yashoj Shakya, Alexa Jorovic, Jeffrey Gauliyar, Gezheb Fasheer, Lutjer Santera, Lutzer Santere, Lutzer Santera Jacob Warner, 28 June 2023, Nature.
DOI: 10.1038/s41586-023-06182-6