Pressure-tuning infrared and Raman microscopy study of the DNA bases: adenine, guanine, cytosine, and thymine

AbstractDiamond-anvil cell, pressure-tuning infrared (IR), and Raman microspectroscopic measurements have been undertaken to examine the effects of high pressures up to about 45 kbar on the vibrational spectra of the four DNA bases, adenine, cytosine, guanine, and thymine. Small structural changes were evident for all the four bases, viz., for adenine and cytosine at 28–31 kbar; for guanine at 16–19 kbar; and for thymine at 25–26 kbar. These changes are most likely associated with alterations in the intermolecular hydrogen-bonding interactions. The pressure dependences of the main peaks observed in the IR spectra of the two phases of guanine lie in the −0.07–0.66 (low-pressure phase) and 0.06–0.91 (high-pressure phase) cm−1/kbar ranges. Also, in the Raman spectra of this nucleoside base, the dν/dP values range from −0.07–0.31 (low-pressure phase) to 0.08–0.50 (high-pressure phase) cm−1/kbar. Similar ranges of dν/dP values were obtained for the other three nucleoside bases.Keywords: infraredRamanmicroscopyDNA basesdiamond-anvil cellhigh pressureadenineguaninecytosinethymine AcknowledgmentsThis research was supported by Discovery and Research Tools and Instrumentation grants from the NSERC (Canada).