Abstract
Poly(L-glutamic acid) is one of the polyamino acids containing a bulky side chain. At the room temperature and at pH<5 it exists in α helical conformation but at pH>7 the α helix is reduced to the random coil state. Normal mode analysis of poly(L-glutamic acid) has been reported by Sengupta and Krimm but no phonon dispersions have been reported so far. As a consequence both the thermodynamical studies and fuller interpretation of spectra remain incomplete. In the present communication we report complete normal mode analysis and full dispersion curves for poly(L-glutamic acid). A comparative study of α and β2 forms of poly(L-glutamic acid) has been carried out in order to identify and to understand the spectral features due to two different conformations. Heat capacity has also been calculated by using density-of-states (g(v)). For the calculation of normal modes the Urey Bradley force field has been used. The normal modes for N-deuterated systems have also been studied to check the validity of the assignments and force field. Our results are in good agreement with the observed experimental data.
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Srivastava, S., Tandon, P., Gupta, V. et al. Heat Capacity and Vibrational Dynamics of Poly(L-glutamic acid) (α Helix). Polym J 29, 33–43 (1997). https://doi.org/10.1295/polymj.29.33
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DOI: https://doi.org/10.1295/polymj.29.33