Vibrational free energy, entropy, and temperature factors of DNA calculated by a helix lattice approach

The vibrational contribution to the free energy, entropy, and the temperature factors of the different atoms in the unit cell are calculated using the method of helix lattice dynamics for the DNA homopolymer poly(dG.poly(dC) in the B conformation. These results are compared to other theoretical calculations and the temperature (B) factors are compared to experiment as well. The problems encountered in using small molecule approximations to describe B factors in DNA like long chain molecules are discussed and a corrected estimate of the temperature factors are presented. Significant differences are found between the different theoretical approaches as reflected in the results of temperature factor calculations.