Infrared studies of DNA, water, and inositol associations

Abstract

Ultraviolet and polarized IR spectra of oriented films of bacterial DNA were recorded over a range of relative humidities (R.H.) between 10 and 84 [degree]/o. The films were made from a DNA gel in H2O or D2O with and without 5 0/0 (w/v) myo-inositol. In the absence of inositol, a large decrease in the dichroic ratio at 1670 cm-1 occurred as the R.H. was lowered between 70 and 30 [degree]/o, indicating the occurrence of considerable disorganization. This was not observed when the DNA was dehydrated in the presence of myo-inositol. A marked increase in absorbance at 2600 A which occurred on lowering the R.H. from 70 - 50 [degree]/o was prevented also by inositol. These results indicate that myo-inositol can replace water molecules and maintain the DNA in the B configuration during dehydration. The possible significance of these observations in the explanation of certain biological phenomena is discussed.