Abstract
The influence of hydration on the nanosecond timescale dynamics of tRNA is investigated using neutron scattering spectroscopy. Unlike protein dynamics, the dynamics of tRNA is not affected by methyl group rotation. This allows for a simpler analysis of the influence of hydration on the conformational motions in RNA. We find that hydration affects the dynamics of tRNA significantly more than that of lysozyme. Both the characteristic length scale and the timescale of the conformational motions in tRNA depend strongly on hydration. Even the characteristic temperature of the so-called "dynamical transition" appears to be hydration-dependent in tRNA. The amplitude of the conformational motions in fully hydrated tRNA is almost twice as large as in hydrated lysozyme. We ascribe these differences to a more open and flexible structure of hydrated RNA, and to a larger fraction and different nature of hydrophilic sites. The latter leads to a higher density of water that makes the biomolecule more flexible. All-atom molecular-dynamics simulations are used to show that the extent of hydration is greater in tRNA than in lysozyme. We propose that water acts as a "lubricant" in facilitating enhanced motion in solvated RNA molecules.
| Original language | English |
|---|---|
| Pages (from-to) | 2755-2762 |
| Number of pages | 8 |
| Journal | Biophysical Journal |
| Volume | 96 |
| Issue number | 7 |
| DOIs | |
| State | Published - 2009 |
Funding
This work was supported by grants from the National Science Foundation (NSF) Polymer Program (to A.P.S.), the NSF (CHE 05-14056 to D.T.), and the NIST Center for Neutron Research (to R.M.B.). This work utilized facilities (NCNR High Flux Backscattering Spectrometer) supported in part by the National Science Foundation under Agreement No. DMR-0454672. We acknowledge the support of the National Institute of Standards and Technology, U.S. Department of Commerce, in providing the neutron research facilities used in this work.