Harvard University led research may have solved the puzzle of how life became molecularly right-handed. In the paper, “Origin of biological homochirality by crystallization of an RNA precursor on a magnetic surface,” published in Science Advances, the researchers explain how it all might have started with the right kind of rocks.
Molecules can be left-handed, right-handed or both. RNA and the sugars that makeup DNA are right-handed molecules. Nobody knows why or if there is a reason beyond chance that life started right-handed.
As an analogy, human hands can be left or right, and they are mirror images of each other, which means that they cannot be superimposed without one facing the wrong way. Molecules can have similar structural symmetry.
In much the same way that right-handed people have difficulty with left-handed scissors, or left-handed guitar players need to reverse strings and play the instrument the other way round, molecules do not interact the same way when they are left or right-handed. Once started, it makes sense that the building blocks of life should continue with the same handedness.
One intriguing idea is that cosmic rays with left-handed spin destroyed left-handed DNA precursors just as life started on Earth.
2023-06-16 05:30:03
Article from phys.org