First-principles study of interaction of serine with nucleobases of DNA and RNA.

The nature of interaction between serine-a vital molecule for cancer cell proliferation and nucleic acid bases-adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U) is investigated within the framework of Møller-Plesset perturbation theory (MP2) and density functional theory (DFT). To quantify the interaction strength between serine and nucleobases, the corresponding binding energies were computed, showing energetic ordering such that G > C > T > A > U. This shows that the interaction energy of serine with guanine is the highest, while with uracil it is the lowest. The amount of charge transferred is the lowest in case of the serine-guanine complex and highest in case of the serine-uracil complex. The results show the serine-guanine complex to be more stable and to have a salt bridge structure involving the -COOH group. Theoretical analysis based on MP2 and DFT shows that the interaction between the serine and nucleobases is mainly determined by hydrogen bonding.