Sequence and temperature dependence of the interbase hydrogen-bond breathing modes in B-DNA polymers: comparison with low-frequency Raman peaks and their role in helix melting.

摘要: We carry out temperature-dependent lattice dynamics calculations to determine the vibrational normal modes associated with interbase H-bond breathing motion in several B-DNA copolymers at temperatures from room temperature melting temperatures. take into consideration Raman selection rules and incorporate a simple empirical model of susceptibility H bonds our calculation compare them measurements. Our are carried using force constants that not further refined low-frequency spectra. show existence strong frequencies relative oscillator strengths close observed peaks range 60–140 cm−1 for DNA sequences considered except one helix. The correlation between calculated indicates frequency likely modes. find these exhibit sizable as well sequence dependence. softening on approaching thermal denaturation is also agreement behavior sensitivity possible reasons discrepancy few values observations discussed. © 1995 John Wiley & Sons, Inc.