@article {2018|2134, title = {DNA Binding Induces a Nanomechanical Switch in the RRM1 Domain of TDP-43}, journal = {J Phys Chem Lett}, volume = {9}, year = {2018}, month = {Jul}, pages = {3800-3807}, abstract = {

Understanding the molecular mechanisms governing protein-nucleic acid interactions is fundamental to many nuclear processes. However, how nucleic acid binding affects the conformation and dynamics of the substrate protein remains poorly understood. Here we use a combination of single molecule force spectroscopy AFM and biochemical assays to show that the binding of TG-rich ssDNA triggers a mechanical switch in the RRM1 domain of TDP-43, toggling between an entropic spring devoid of mechanical stability and a shock absorber bound-form that resists unfolding forces of \∼40 pN. The fraction of mechanically resistant proteins correlates with an increasing length of the TG n oligonucleotide, demonstrating that protein mechanical stability is a direct reporter of nucleic acid binding. Steered molecular dynamics simulations on related RNA oligonucleotides reveal that the increased mechanical stability fingerprinting the holo-form is likely to stem from a unique scenario whereby the nucleic acid acts as a \"mechanical staple\" that protects RRM1 from mechanical unfolding. Our approach highlights nucleic acid binding as an effective strategy to control protein nanomechanics.

}, doi = {10.1021/acs.jpclett.8b01494}, author = {Wang, Yong Jian and Rico-Lastres, Palma and Lezamiz, Ainhoa and Mora, Marc and Solsona, Carles and Guillaume Stirnemann and Garcia-Manyes, Sergi} } @article {2011|1690, title = {Dynamics of water in concentrated solutions of amphiphiles: Key roles of local structure and aggregation}, journal = {J. Phys. Chem. B}, volume = {115}, year = {2011}, pages = {3254{\textendash}3262}, abstract = {

Water translational and reorientational dynamics in concentrated solutions of amphiphiles are investigated through molecular dynamics simulations and analytic modeling. We evidence the critical importance of the solute concentration in determining the magnitude of the slowdown in water dynamics compared to the bulk situation. The comparison of concentrated aqueous solutions of tetramethylurea, which tends to aggregate, and of trimethylamine N-oxide, which does not, shows the dramatic impact of solute clustering on the water dynamics. No significant decoupling of the reorientation and translation dynamics of water is observed, even at very high solute concentrations. The respective roles of energetic and topological disorders in determining the translational subdiffusive water dynamics in these confining environments are discussed. The water reorientational dynamics is shown to be quantitatively described by an extended jump model which combines two factors determined by the local structure: the transition-state excluded volume and the transition-state hydrogen-bond strength.

}, issn = {15206106}, author = {Guillaume Stirnemann and Fabio Sterpone and Laage, Damien} } @article {2010|1696, title = {Direct evidence of angular jumps during water reorientation through two-dimensional infrared anisotropy}, journal = {J. Phys. Chem. Lett.}, volume = {1}, year = {2010}, pages = {1511{\textendash}1516}, abstract = {

Water reorientation was recently suggested via simulations to proceed through large angular jumps, but direct experimental evidence has so far remained elusive. Here we show that both infrared pump-probe and photon echo spectroscopies can provide such evidence through the measurement of the two-dimensional anisotropy decay. We calculate these two-dimensional anisotropies from simulations and show they can be interpreted as a vibrational frequency-dependent resolved orientation time-correlation function. We develop a frequency-dependent extended jump model to predict the nature of the angular jump signature in these anisotropies. This model provides a rigorous and unambiguous connection between ultrafast infrared experimental results and the presence of angular jumps in bulk water, and calls for new experiments.

}, issn = {19487185}, doi = {10.1021/jz100385r}, author = {Guillaume Stirnemann and Laage, Damien} } @article {2008|1695, title = {Does water condense in hydrophobic cavities? A molecular simulation study of hydration in heterogeneous nanopores}, journal = {J. Phys. Chem. C}, volume = {112}, year = {2008}, pages = {10435{\textendash}10445}, author = {Cailliez, Fabien and Guillaume Stirnemann and Boutin, Anne and Demachy, Isabelle and Fuchs, Alain H.} }