Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2012 Oct 3;103(7):1566-75.
doi: 10.1016/j.bpj.2012.08.046. Epub 2012 Oct 2.

Dynamics of protein and its hydration water: neutron scattering studies on fully deuterated GFP

Jonathan D Nickels  1 , Hugh O'Neill, Liang Hong, Madhusudan Tyagi, Georg Ehlers, Kevin L Weiss, Qiu Zhang, Zheng Yi, Eugene Mamontov, Jeremy C Smith, Alexei P Sokolov
Affiliations

Dynamics of protein and its hydration water: neutron scattering studies on fully deuterated GFP

Jonathan D Nickels et al. Biophys J. .

Abstract

We present a detailed analysis of the picosecond-to-nanosecond motions of green fluorescent protein (GFP) and its hydration water using neutron scattering spectroscopy and hydrogen/deuterium contrast. The analysis reveals that hydration water suppresses protein motions at lower temperatures (<~ 200 K), and facilitates protein dynamics at high temperatures. Experimental data demonstrate that the hydration water is harmonic at temperatures <~ 180-190 K and is not affected by the proteins' methyl group rotations. The dynamics of the hydration water exhibits changes at ~ 180-190 K that we ascribe to the glass transition in the hydrated protein. Our results confirm significant differences in the dynamics of protein and its hydration water at high temperatures: on the picosecond-to-nanosecond timescale, the hydration water exhibits diffusive dynamics, while the protein motions are localized to <~3 Å. The diffusion of the GFP hydration water is similar to the behavior of hydration water previously observed for other proteins. Comparison with other globular proteins (e.g., lysozyme) reveals that on the timescale of 1 ns and at equivalent hydration level, GFP dynamics (mean-square displacements and quasielastic intensity) are of much smaller amplitude. Moreover, the suppression of the protein dynamics by the hydration water at low temperatures appears to be stronger in GFP than in other globular proteins. We ascribe this observation to the barrellike structure of GFP.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Structure of GFP, from PDB:1GFL (29).
Figure 2
Figure 2
Temperature variation of mean-squared displacements. (a) 〈r2〉 in d-GFP/H2O reflects motions of hydration water. (Inset) 〈r2〉 in dry h-GFP, h-GFP/D2O, and d-GFP/H2O. (b) 〈r2〉 in h-GFP/D2O (solid circles) and dry h-GFP (open triangles). The difference (open squares) monotonically decreases with temperature up to T ∼ 200 K.
Figure 3
Figure 3
Quasielastic neutron scattering spectra of h-GFP/D2O and d-GFP/H2O samples at T = 170 K, summed over all Q. (Line) Spectrum of d-GFP/H2O sample at T = 4 K that presents the resolution function of the HFBS spectrometer.
Figure 4
Figure 4
QENS spectra measured on HFBS spectrometer and summed over all Q at T = 220 K (a) and at T = 280 K (b) for h-GFP/D2O and d-GFP/H2O. (Lines) Resolution function.
Figure 5
Figure 5
QENS spectra in a broader energy range measured on BASIS spectrometer and summed over all Q at T = 220 K (a) and at T = 280 K (b) for dry h-GFP, h-GFP/D2O, and d-GFP/H2O. (Lines) Resolution function.
Figure 6
Figure 6
Dynamic structure factor from inelastic neutron scattering of d-GFP/H2O (red circles), h-GFP/D2O (blue squares), and dry h-GFP (black triangles) samples at T = 170 K. The spectra are summed over all measured Q (0.5–5 Å−1). Dry h-GFP shows the highest QENS spectrum at E < 1 meV.
Figure 7
Figure 7
Susceptibility spectra of d-GFP/H2O sample at different Q (shown by numbers), measured at T = 280 K. (Lines) Fits to the Cole-Cole function.
Figure 8
Figure 8
Q-dependence of the relaxation time in the d-GFP/H2O spectra (solid squares) at T = 280 K obtained from the fit to the Cole-Cole function (Fig. 7). (Solid line) Fit by a power law. (Open circles) τ of the bulk water from Russo et al. (45) measured at T = 295 K. (Dashed line) Fit of the bulk water data shifted by a factor 1.45 (the ratio of viscosities at T = 280 K and T = 295 K) to take into account the difference in temperature.
Figure 9
Figure 9
Susceptibility spectra of (a) dry h-GFP and (b) h-GFP/D2O measured at different Q at T = 280 K.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Austin R.H., Beeson K.W., Gunsalus I.C. Dynamics of ligand binding to myoglobin. Biochemistry. 1975;14:5355–5373. - PubMed
    1. Frauenfelder H., Sligar S.G., Wolynes P.G. The energy landscapes and motions of proteins. Science. 1991;254:1598–1603. - PubMed
    1. Henzler-Wildman K., Kern D. Dynamic personalities of proteins. Nature. 2007;450:964–972. - PubMed
    1. Henzler-Wildman K.A., Lei M., Kern D. A hierarchy of timescales in protein dynamics is linked to enzyme catalysis. Nature. 2007;450:913–916. - PubMed
    1. Beece D., Eisenstein L., Yue K.T. Solvent viscosity and protein dynamics. Biochemistry. 1980;19:5147–5157. - PubMed

Publication types

LinkOut - more resources