Protein dynamics studied by neutron scattering

Abstract

1. Introduction 3282. Basic concepts of neutron scattering 3292.1 Introduction 3292.2 Neutron-scattering functions 3312.3 Coherent and incoherent neutron scattering. The particular role of hydrogen in incoherent scattering 3322.4 Total elastic scattering, EISF and mean square displacement (MSD) 3332.5 Quasielastic scattering and relaxation function 3342.6 Inelastic scattering and density of states 3353. Experimental aspects and instruments 3353.1 Energy and space resolution 3353.2 General sample aspects 3353.3 Potential effects of D2O on dynamics 3363.4 Experimental 2H (deuterium) labelling 3364. Physics of protein dynamics 3364.1 Models 3364.2 The dynamical transition 3384.3 Effective force constants 3395. Dynamics of hydrated protein powders 3395.1 First experiments on myoglobin 3405.2 Dynamical transitions in other proteins 3405.3 The role of hydration water 3415.4 Influence of the solvent 3445.5 Diffusional motions within proteins by QENS 3465.6 Inelastic neutron scattering and vibrational spectra 3475.7 Conclusions 3516. Membranes 3526.1 Lipid bilayers 3536.2 BR and the purple membrane (PM) 3536.2.1 The dynamical transition in the PM 3536.2.2 QENS from oriented PM 3546.2.3 Hydration dependence of PM motions 3556.2.4 Local dynamics in PM studied by isotope labelling 3566.2.5 Dynamics of different BR conformations 3577. Protein solutions 3587.1 From powders to solutions 3587.2 Water dynamics and solvent dependence of the dynamical transition in proteins 3598. Comparing neutron scattering with other techniques 3599. Biological relevance 3609.1 Dynamics–activity relations 3609.2 Dynamics–stability relations (adaptation to extreme environments) 3609.3 Protein folding 36110. Acknowledgements 36411. References 364This review of protein dynamics studied by neutron scattering focuses on data collected in the last 10 years. After an introduction to thermal neutron scattering and instrumental aspects, theoretical models that have been used to interpret the data are presented and discussed. Experiments are described according to sample type, protein powders, solutions and membranes. Neutron-scattering results are compared to those obtained from other techniques. The biological relevance of the experimental results is discussed. The major conclusion of the last decade concerns the strong dependence of internal dynamics on the macromolecular environment.