Collective vibrational modes in molecular assembly of DNA and its application to biological systems. Low frequency Raman spectroscopy

Abstract

The origin of low frequency modes in a molecular assembly of DNA has been investigated by changing the assembly conditions of DNA molecules. The ∼85 cm−1 broadband in B form DNA was found to be insensitive of the assembly condition, and was ascribed mainly to motions of base pairs bound with hydrogen bonds. The lowest frequency mode was found, on the contrary, to be sensitive to the assembly condition and therefore considered to include motions of backbone chains. Through the observation of the lowest frequency mode in B-form DNA in biological systems such as lambda phage, chromatin and nucleosome core, we have concluded that from the dynamical point of view the DNA molecules in biological systems is more likely in a solid state than in an aqueous solution state.