@article {2020|2140, title = {Structural transitions in the RNA 7SK 5{\textquoteright} hairpin and their effect on HEXIM binding}, journal = {Nucleic Acids Res}, volume = {48}, year = {2020}, month = {01}, pages = {373-389}, abstract = {

7SK RNA, as part of the 7SK ribonucleoprotein complex, is crucial to the regulation of transcription by RNA-polymerase II, via its interaction with the positive transcription elongation factor P-TEFb. The interaction is induced by binding of the protein HEXIM to the 5\&$\#$39; hairpin (HP1) of 7SK RNA. Four distinct structural models have been obtained experimentally for HP1. Here, we employ computational methods to investigate the relative stability of these structures, transitions between them, and the effects of mutations on the observed structural ensembles. We further analyse the results with respect to mutational binding assays, and hypothesize a mechanism for HEXIM binding. Our results indicate that the dominant structure in the wild type exhibits a triplet involving the unpaired nucleotide U40 and the base pair A43-U66 in the GAUC/GAUC repeat. This conformation leads to an open major groove with enough potential binding sites for peptide recognition. Sequence mutations of the RNA change the relative stability of the different structural ensembles. Binding affinity is consequently lost if these changes alter the dominant structure.

}, doi = {10.1093/nar/gkz1071}, author = {R{\"o}der, Konstantin and Guillaume Stirnemann and Dock-Bregeon, Anne-Catherine and Wales, David J and Pasquali, Samuela} } @booklet {2018|2066, title = {Ten simple rules to create a serious game, illustrated with examples from structural biology}, year = {2018}, author = {Marc Baaden and Delalande, Olivier and Nicolas F{\'e}rey and Pasquali, Samuela and Waldisp{\"u}hl, J{\'e}r{\^o}me and Antoine Taly} } @article {2017|2041, title = {Fast coarse-grained model for RNA titration.}, journal = {J Chem Phys}, volume = {146}, year = {2017}, month = {2017 Jan 21}, pages = {035101}, abstract = {

A new numerical scheme for RNA (ribonucleic acid) titration based on the Debye-H{\"u}ckel framework for the salt description is proposed in an effort to reduce the computational costs for further applications to study protein-RNA systems. By means of different sets of Monte Carlo simulations, we demonstrated that this new scheme is able to correctly reproduce the experimental titration behavior and salt pKshifts. In comparison with other theoretical approaches, similar or even better outcomes are achieved at much lower computational costs. The model was tested on the lead-dependent ribozyme, the branch-point helix, and the domain 5 from Azotobacter vinelandii Intron 5.

}, keywords = {Azotobacter vinelandii, Introns, Models, Chemical, Molecular Dynamics Simulation, Monte Carlo Method, Protein Structure, Secondary, Protons, RNA, RNA, Catalytic, Titrimetry}, issn = {1089-7690}, doi = {10.1063/1.4972986}, author = {Barroso da Silva, Fernando Luis and Philippe Derreumaux and Pasquali, Samuela} } @article {2017|2037, title = {Multifunctional energy landscape for a DNA G-quadruplex: An evolved molecular switch.}, journal = {J Chem Phys}, volume = {147}, year = {2017}, month = {2017 Oct 21}, pages = {152715}, abstract = {

We explore the energy landscape for a four-fold telomere repeat, obtaining interconversion pathways between six experimentally characterised G-quadruplex topologies. The results reveal a multi-funnel system, with a variety of intermediate configurations and misfolded states. This organisation is identified with the intrinsically multi-functional nature of the system, suggesting a new paradigm for the classification of such biomolecules and clarifying issues regarding apparently conflicting experimental results.

}, issn = {1089-7690}, doi = {10.1063/1.4997377}, author = {Cragnolini, Tristan and Chakraborty, Debayan and Sponer, Jiri and Philippe Derreumaux and Pasquali, Samuela and Wales, David J} } @article {2017|2038, title = {Protein-RNA complexation driven by the charge regulation mechanism.}, journal = {Biochem Biophys Res Commun}, year = {2017}, month = {2017 Jul 12}, abstract = {

Electrostatic interactions play a pivotal role in many (bio)molecular association processes. The molecular organization and function in biological systems are largely determined by these interactions from pure Coulombic contributions to more peculiar mesoscopic forces due to ion-ion correlation and proton fluctuations. The latter is a general electrostatic mechanism that gives attraction particularly at low electrolyte concentrations. This charge regulation mechanism due to titrating amino acid and nucleotides residues is discussed here in a purely electrostatic framework. By means of constant-pH Monte Carlo simulations based on a fast coarse-grained titration proton scheme, a new computer molecular model was devised to study protein-RNA interactions. The complexation between the RNA silencing suppressor p19 viral protein and the 19-bp small interfering RNA was investigated at different solution pH and salt conditions. The outcomes illustrate the importance of the charge regulation mechanism that enhances the association between these macromolecules in a similar way as observed for other protein-polyelectrolyte systems typically found in colloidal science. Due to the highly negative charge of RNA, the effect is more pronounced in this system as predicted by the Kirkwood-Shumaker theory. Our results contribute to the general physico-chemical understanding of macromolecular complexation and shed light on the extensive role of RNA in the cell\&$\#$39;s life.

}, issn = {1090-2104}, doi = {10.1016/j.bbrc.2017.07.027}, author = {Barroso da Silva, Fernando Luis and Philippe Derreumaux and Pasquali, Samuela} } @article {2017|2042, title = {What Can Human-Guided Simulations Bring to RNA Folding?}, journal = {Biophys J}, volume = {113}, year = {2017}, month = {2017 Jul 25}, pages = {302-312}, abstract = {

Inspired by the recent success of scientific-discovery games for predicting protein tertiary and RNA secondary structures, we have developed an open software for coarse-grained RNA folding simulations, guided by human intuition. To determine the extent to which interactive simulations can accurately predict 3D RNA structures of increasing complexity and lengths (four RNAs with 22-47 nucleotides), an interactive experiment was conducted with 141 participants who had very little knowledge of nucleic acids systems and computer simulations, and had received only a brief description of the important forces stabilizing RNA structures. Their structures and full trajectories have been analyzed statistically and compared to standard replica exchange molecular dynamics simulations. Our analyses show that participants gain easily chemical intelligence to fold simple and nontrivial topologies, with little computer time, and this result opens the door for the use of human-guided simulations to RNA folding. Our experiment shows that interactive simulations have better chances of success when the user widely explores the conformational space. Interestingly, providing on-the-fly feedback of the root mean square deviation with respect to the experimental structure did not improve the quality of the proposed models.

}, keywords = {Access to Information, Computer Simulation, Feedback, Psychological, Humans, Internet, Models, Genetic, Models, Molecular, RNA, RNA Folding, Software, Solvents}, issn = {1542-0086}, doi = {10.1016/j.bpj.2017.05.047}, author = {Mazzanti, Liuba and Doutreligne, S{\'e}bastien and Gageat, Cedric and Philippe Derreumaux and Antoine Taly and Marc Baaden and Pasquali, Samuela} } @article {2016|1707, title = {Coarse-Grained Simulations Complemented by Atomistic Molecular Dynamics Provide New Insights into Folding and Unfolding of Human Telomeric G-Quadruplexes}, journal = {J. Chem. Theory Comput.}, volume = {12}, number = {12}, year = {2016}, month = {dec}, pages = {6077{\textendash}6097}, abstract = {G-quadruplexes are the most important non canonical DNA architectures. Many quadruplex-forming sequences, including the human telomeric sequence d(GGGTTA)(n), have been investigated due to their implications in cancer and other diseases, and because of their potential in DNA-based nanotechnology. Despite the availability of atomistic structural studies of folded G-quadruplexes, their folding pathways remain mysterious, and mutually contradictory models of folding coexist in the literature. Recent experiments convincingly demonstrated that G-quadruplex folding often takes days to reach thermodynamic equilibrium. Based on atomistic simulations of diverse classes of intermediates in G-quadruplex folding, we have suggested that the folding is an extremely multipathway process combining a kinetic partitioning mechanism with conformational diffusion. However, complete G-quadruplex folding is far beyond the time scale of atomistic simulations. Here we use high-resolution coarse-grained simulations to investigate potential unfolding intermediates, whose structural dynamics are then further explored with all-atom simulations. This multiscale approach indicates how various pathways are interconnected in a complex network. Spontaneous conversions between different folds are observed. We demonstrate the inability of simple order parameters, such as radius of gyration or the number of native H-bonds, to describe the folding landscape of the G-quadruplexes. Our study also provides information relevant to further development of the coarse grained force field.}, issn = {1549-9618}, doi = {10.1021/acs.jctc.6b00667}, author = {Stadlbauer, Petr and Mazzanti, Liuba and Cragnolini, Tristan and Wales, David J. and Philippe Derreumaux and Pasquali, Samuela and Sponer, Jiri} } @article {2016|1765, title = {Electrostatics analysis of the mutational and pH effects of the N-terminal domain self-association of the major ampullate spidroin}, journal = {Soft Matter}, volume = {12}, number = {25}, year = {2016}, pages = {5600{\textendash}5612}, abstract = {Spider silk is a fascinating material combining mechanical properties such as maximum strength and high toughness comparable or better than man-made materials, with biocompatible degradability characteristics. Experimental measurements have shown that pH triggers the dimer formation of the N-terminal domain (NTD) of the major ampullate spidroin 1 (MaSp 1). A coarse-grained model accounting for electrostatics, van der Waals and pH-dependent charge-fluctuation interactions, by means of Monte Carlo simulations, gave us a more comprehensive view of the NTD dimerization process. A detailed analysis of the electrostatic properties and free energy derivatives for the NTD homoassociation was carried out at different pH values and salt concentrations for the protein wild type and for several mutants. We observed an enhancement of dipole-dipole interactions at pH 6 due to the ionization of key amino acids, a process identified as the main driving force for dimerization. Analytical estimates based on the DVLO theory framework corroborate our findings. Molecular dynamics simulations using the OPEP coarse-grained force field for proteins show that the mutant E17Q is subject to larger structural fluctuations when compared to the wild type. Estimates of the association rate constants for this mutant were evaluated by the Debye-Smoluchowski theory and are in agreement with the experimental data when thermally relaxed structures are used instead of the crystallographic data. Our results can contribute to the design of new mutants with specific association properties.}, issn = {1744-683X}, doi = {10.1039/c6sm00860g}, author = {Barroso da Silva, Fernando Luis and Pasquali, Samuela and Philippe Derreumaux and Dias, Luis Gustavo} } @article {2015|1716, title = {Ab initio RNA folding}, journal = {Journal of Physics-condensed Matter}, volume = {27}, number = {23}, year = {2015}, month = {jun}, pages = {233102}, doi = {10.1088/0953-8984/27/23/233102}, author = {Cragnolini, Tristan and Philippe Derreumaux and Pasquali, Samuela} } @article {2015|1634, title = {Amyloid beta Protein and Alzheimer{\textquoteright}s Disease: When Computer Simulations Complement Experimental Studies}, journal = {Chem. Rev.}, volume = {115}, number = {9}, year = {2015}, month = {may}, pages = {3518{\textendash}3563}, doi = {10.1021/cr500638n}, author = {Nasica-Labouze, Jessica and Phuong Hoang Nguyen and Fabio Sterpone and Berthoumieu, Olivia and Buchete, Nicolae-Viorel and Cote, Sebastien and De Simone, Alfonso and Doig, Andrew J. and Faller, Peter and Garcia, Angel and Laio, Alessandro and Li, Mai Suan and Melchionna, Simone and Mousseau, Normand and Mu, Yuguang and Paravastu, Anant and Pasquali, Samuela and Rosenman, David J. and Strodel, Birgit and Tarus, Bogdan and Viles, John H. and Zhang, Tong and Wang, Chunyu and Philippe Derreumaux} } @article {2015|1708, title = {Coarse-Grained HiRE-RNA Model for ab Initio RNA Folding beyond Simple Molecules, Including Noncanonical and Multiple Base Pairings}, journal = {J. Chem. Theory Comput.}, volume = {11}, number = {7}, year = {2015}, pages = {3510{\textendash}3522}, doi = {10.1021/acs.jctc.5b00200}, author = {Cragnolini, Tristan and Laurin, Yoann and Philippe Derreumaux and Pasquali, Samuela} } @article {2015|1780, title = {{E}pock: rapid analysis of protein pocket dynamics}, journal = {Bioinformatics}, volume = {31}, number = {9}, year = {2015}, month = {may}, pages = {1478{\textendash}1480}, doi = {10.1093/bioinformatics/btu822}, author = {Laurent, Benoist and Matthieu Chavent and Cragnolini, Tristan and Dahl, Anna Caroline E. and Pasquali, Samuela and Philippe Derreumaux and Sansom, Mark S. P. and Marc Baaden} } @conference {2014|1784, title = {Coarse-Grain RNA Folding: Towards More Complex Structures}, booktitle = {Biophys. J.}, volume = {106}, number = {2, 1}, year = {2014}, note = {58th Annual Meeting of the Biophysical-Society, San Francisco, CA, FEB 15-19, 2014}, month = {jan}, pages = {283A}, author = {Cragnolini, Tristan and Laurin, Yoann and Philippe Derreumaux and Pasquali, Samuela} } @conference {2014|1783, title = {Wide Exploration of OPEP Protein Energy Landscapes using Advanced Monte Carlo Methods}, booktitle = {Biophys. J.}, volume = {106}, number = {2, 1}, year = {2014}, note = {58th Annual Meeting of the Biophysical-Society, San Francisco, CA, FEB 15-19, 2014}, month = {jan}, pages = {256A}, author = {Cragnolini, Tristan and Sutherland-Cash, Kyle H. and Wales, David and Pasquali, Samuela and Philippe Derreumaux} } @article {2013|1923, title = {Coarse-Grained Simulations of RNA and DNA Duplexes}, journal = {J. Phys. Chem. B}, volume = {117}, number = {27}, year = {2013}, month = {jul}, pages = {8047{\textendash}8060}, doi = {10.1021/jp400786b}, author = {Cragnolini, Tristan and Philippe Derreumaux and Pasquali, Samuela} } @article {2012|1920, title = {The Coarse-Grained OPEP Force Field for Non-Amyloid and Amyloid Proteins}, journal = {J. Phys. Chem. B}, volume = {116}, number = {30}, year = {2012}, month = {aug}, pages = {8741{\textendash}8752}, doi = {10.1021/jp301665f}, author = {Y Chebaro and Pasquali, Samuela and Philippe Derreumaux} } @article {2011|1889, title = {Impact of Thermostats on Folding and Aggregation Properties of Peptides Using the Optimized Potential for Efficient Structure Prediction Coarse-Grained Model}, journal = {J. Chem. Theory Comput.}, volume = {7}, number = {5}, year = {2011}, month = {may}, pages = {1502{\textendash}1510}, doi = {10.1021/ct100619p}, author = {Spill, Yannick G. and Pasquali, Samuela and Philippe Derreumaux} } @article {2010|1917, title = {HiRE-RNA: A High Resolution Coarse-Grained Energy Model for RNA}, journal = {J. Phys. Chem. B}, volume = {114}, number = {37}, year = {2010}, month = {sep}, pages = {11957{\textendash}11966}, doi = {10.1021/jp102497y}, author = {Pasquali, Samuela and Philippe Derreumaux} }