VIBRATIONAL DYNAMICS AND HEAT-CAPACITY OF POLY(L-LYSINE)

Poly(L-lysine) is a polypeptide having a bulky hydrophobic side chain. A systematic study of the full vibrational dynamics, including phonon dispersion, for the alpha-helical form of this biopolymer has been re ported using Wilson's GF matrix method as modified by Higgs for an inf inite polymeric chain. The calculated frequencies explain well the IR and Raman spectra. A comparison of the amide modes with other alpha-he lical polypeptides is reported here. Spectral frequencies have been ob tained for the N-deuterated species to check the validity of force fie ld and correctness of assignments. Heat capacity has also been calcula ted from dispersion curves via density-of-states using Debye relation in the temperature range 50-500 K. The calculated values are found to be in close agreement with the recent experimental data of Roles el al .