Vibrational neutron spectroscopy of collagen and model polypeptides

H. D. Middendorf, R. L. Hayward, S. F. Parker, J. Bradshaw, A. Miller

Research output: Contribution to journalArticle

Abstract

A pulsed source neutron spectrometer has been used to measure vibrational spectra (20–4000 cm-1) of dry and hydrated type I collagen fibers, and of two model polypeptides, polyproline II and (prolyl-prolyl-glycine)10, at temperatures of 30 and 120 K. the collagen spectra provide the first high resolution neutron views of the proton-dominated modes of a protein over a wide energy range from the low frequency phonon region to the rich spectrum of localized high frequency modes. Several bands show a level of fine structure approaching that of optical data. The principal features of the spectra are assigned. A difference spectrum is obtained for protein associated water, which displays an acoustic peak similar to pure ice and a librational band shifted to lower frequency by the influence of the protein. Hydrogen-weighted densities of states are extracted for collagen and the model polypeptides, and compared with published calculations. Proton mean-square displacements are calculated from Debye-Waller factors measured in parallel quasi-elastic neutron-scattering experiments. Combined with the collagen density of states function, these yield an effective mass of 14.5 a.m.u. for the low frequency harmonic oscillators, indicating that the extended atom approximation, which simplifies analyses of low frequency protein dynamics, is appropriate.

Original languageEnglish
Pages (from-to)660-673
Number of pages14
JournalBiophysical Journal
Volume69
Issue number2
DOIs
Publication statusPublished - 1 Aug 1995

ASJC Scopus subject areas

  • Biophysics

Cite this

Vibrational neutron spectroscopy of collagen and model polypeptides. / Middendorf, H. D.; Hayward, R. L.; Parker, S. F.; Bradshaw, J.; Miller, A.

In: Biophysical Journal, Vol. 69, No. 2, 01.08.1995, p. 660-673.

Research output: Contribution to journalArticle

Middendorf, H. D. ; Hayward, R. L. ; Parker, S. F. ; Bradshaw, J. ; Miller, A. / Vibrational neutron spectroscopy of collagen and model polypeptides. In: Biophysical Journal. 1995 ; Vol. 69, No. 2. pp. 660-673.
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