Quantum Mechanical Origin of Genetic Material in Minimal Cells

We used quantum mechanical nonlocal gradient electron correlation interactions density functional theory methods to investigate various self-assembled photoactive bioorganic systems of artificial minimal living cells. The cell systems studied are based on sensitizer squarine, 8-oxo-guanine, cytosine, fatty acid, water molecules and consisted of around 300 atoms and are up to about 4 nm in diameter. The quantum mechanical based electron correlation interactions that originate the weak hydrogen and Van der Waals chemical bonds. The impact of these bonds increase in strength with the addition of a polar solvent molecules (water or methanol) and thus play a critical role in the self assembly and functioning of a system consisting of a photosynthetic center, and fatty acid and precursor of fatty acid molecules (pFA). The distances between the separated sensitizer, precursor of fatty acid, and water molecules are comparable to Van der Waals and hydrogen bonding radii. As a result these nonlinear quantum interactions compress the overall system resulting in a smaller gap between the HOMO and LUMO electron energy levels and photoexcited electron tunneling occurs from the sensitizer to pFA. The most intense excited states of minimal cells are partially composed of LUMO+n located on precursors of fatty acid when the bis(4-diphenylamine-2-phenyl)-squarine molecule is covalently attached to 8-oxo-guanine and that promote electron hoping (tunneling) on the pFA molecules. The photoexcited electron is hoping (tunneling) on the head (the waste piece) of pFA molecules and further split these molecules due to intense rotations and vibrations of the weak chemical bond joining the waste piece with fatty acid piece. The most intense absorption lines of investigated minimal cels containing the squarine–guanine supermolecule based derivatives shifts to red due to the more complexity. Addition the guanine molecule to squarine molecule leads to the absorption spectrum which cover the more wide region of visible spectrum. The shift of the intense absorption line to the red allow for the minimal artificial living cell to absorb the light in the longer wavelength region (early in the morning and in the evening). That most probably allowed better compete for such a kind of first protocells in getting the food molecules. We can state that quantum mechanical processes originated the emergence of genetic material (8-oxo-guanine) in the protocells at the early stages of emergence of life in the Earth.