Evidence of a Preresonance Raman Effect of the Base Residue in a Nucleic Acid

Abstract

Abstract The Ramam spectra of β-uridine-5′-phosphoric acid (UMP), its deuterated product, β-uridine-3′-β-uridine-5′-phosphoric acid (UpU), and polyribouridylic acid (poly U) have been observed in their aqueous solutions; and the Raman lines assignable to the phosphate group and to the base residue have been indicated. For UMP, the intensity ratio of a Raman line of the base residue versus that of the phosphate group was found to become greater on changing the exciting line from the 6328 Å line of a helium-neon laser to the 4880 Å line of an argon ion laser. This fact has been taken as indicating that a preresonance Raman effect takes place of the base residue with the effective absorption at 2600 Å.