Browsing by Author "Mulder, FAA"

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    Low-temperature inflection observed in neutron scattering measurements of proteins is due to methyl rotation: direct evidence using isotope labeling and molecular dynamics simulations
    (American Chemical Society, 2010-04-14) Wood, K; Tobias, DJ; Kessler, B; Gabel, F; Oesterhelt, D; Mulder, FAA; Zaccai, G; Weik, M
    There is increasing interest in the contribution of methyl groups to the overall dynamics measured by neutron scattering experiments of proteins. In particular an inflection observed in atomic mean square displacements measured as a function of temperature on high resolution spectrometers (~1 μeV) was explained by the onset of methyl group rotations. By specifically labeling a non-methyl-containing side-chain in a native protein system, the purple membrane, and performing neutron scattering measurements, we here provide direct experimental evidence that the observed inflection is indeed due to methyl group rotations. Molecular dynamics simulations reproduce the experimental data, and their analysis suggests that the apparent transition is due to methyl group rotation entering the finite instrumental resolution of the spectrometer. Methyl group correlation times measured by solid state NMR in the purple membrane, taken from previous work, support the interpretation. © 2010, American Chemical Society
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    Protein surface and core dynamics show concerted hydration-dependent activation
    (Wiley-V C H Verlag GMBH, 2013-01-01) Wood, K; Gallat, FX; Otten, R; van Heel, AJ; Lethier, M; van Eijck, L; Moulin, M; Haertlein, M; Weik, M; Mulder, FAA
    By specifically labeling leucine/valine methyl groups and lysine side chains “inside” and “outside” dynamics of proteins on the nanosecond timescale are compared using neutron scattering (see picture). Surprisingly, both groups display similar dynamics as a function of temperature, and the buried hydrophobic core is sensitive to hydration and undergoes a dynamical transition. © 2013, Wiley-VCH Verlag GmbH & Co. KGaA