High-Resolution Vibrational Inelastic Neutron Scattering:  A New Spectroscopic Tool for Globular Proteins

Abstract

Inelastic neutron scattering is a form of vibrational spectroscopy for which the measured scattering intensities are directly related to vibrational amplitudes, allowing, in principle, convenient comparison with theoretical dynamical models. However, until recently, neutron sources and instruments have not allowed spectra to be collected on globular proteins with useful energy resolutions in the frequency range of most macromolecular vibrations (∼50−3500 cm-1). The construction of the time-focussing crystal analyzer (TFXA) spectrometer at the ISIS pulsed neutron source near Oxford has changed this situation, allowing high-resolution spectra to be obtained over the whole frequency range of interest. We present here TFXA vibrational spectra of the enzyme, Staphylococcal nuclease, and compare the results with spectra calculated from a normal mode analysis of the protein using the program CHARMM (see ref ). The calculated spectral intensities, which were obtained using a force field that was not refined to fit the present experimental data, are in general agreement with experiment and are used to assign the peaks.

Amplitudes and directions of internal protein motions from a JAM analysis of15N relaxation data

“…Another example is the comparison between neutron scattering data and normal-mode analysis. 17 The latter study concludes that dynamics structure factors determined from experiment and normal mode agree very well. In this paper, intersubstate motions were simulated to reproduce the ensemble average of the physical quantity and statistical weights of possible conformational substates were fitted to match the experimental data.…”

Neutron Inelastic Scattering as a High‐Resolution Vibrational Spectroscopy: New Tool for the Study of Protein Dynamics

“…We succeeded to record INS spectrum of SNase at 25 K in the region between 200 and 3500 cm −1 with good quality [2]. The spectrum was compared with the normal mode analysis of SNase [2]. The calculated spectrum, which was obtained using a force field that was not refined to fit the present experimental data, is in general agreement with experiment and are used to assign the peaks.…”

“…Using Staphylococcal nuclease (SNase), we have been investigating the protein dynamics with INS over a wide range of frequency [2,3]. We succeeded to record INS spectrum of SNase at 25 K in the region between 200 and 3500 cm −1 with good quality [2]. The spectrum was compared with the normal mode analysis of SNase [2].…”

Inelastic neutron scattering spectroscopy of C60@calix[8]arene

“…Besides the previous work of [21], it may be worth mentioning that our approach is rather similar to that adopted recently to simulate the spectrum of a small protein [28].…”