@article {2019|2128, title = {Probable Transmembrane Amyloid α-Helix Bundles Capable of Conducting Ca Ions.}, journal = {J Phys Chem B}, volume = {123}, year = {2019}, month = {2019 Mar 28}, pages = {2645-2653}, abstract = {

Amyloid β (Aβ) peptides are considered the major causative agents of Alzheimer\&$\#$39;s disease (AD). In a widely accepted mechanism for AD pathogenesis, Aβ peptides are proposed to play multiple roles in damaging brain cells and their synaptic communications. Due to the heterogeneous nature of Aβ oligomers, their in vivo structures have not been understood. Most experimental and computational studies favored β-rich structures of Aβ as observed in Aβ fibrils. In this in silico study, we investigated an alternative perspective on the structures and function of Aβ oligomers in the cell membrane. Transmembrane α-helix bundles of the Aβ tetramer and trimer were observed in extensive temperature replica exchange molecular dynamics (REMD) simulations. We observed three minima on the free-energy landscape of each oligomer, namely, A, B, and C for the tetramer and D, E, and F for the trimer. Except for F, the minima consist of 4 or 3 parallel helices spanning across the membrane model dipalmitoylphosphatidylcholine. Replica exchange molecular dynamics-umbrella sampling (REMD-US) simulation was applied to study the process of a Ca crossing the pore formed by the α-helix bundles in A-E in comparison to that in a calcium channel and a proton channel. REMD-US reveals that A, C, and D allow Ca to cross their pore with a free-energy barrier comparable to that found for the calcium channel. In contrast, the free-energy barrier of a Ca ion crossing B, E, and the proton channel is significantly higher. This result suggests that Aβ peptide oligomers could form transmembrane α-helix bundles that provide feasible pathways for Ca transport. This is an intriguing observation that will stimulate further studies.

}, issn = {1520-5207}, doi = {10.1021/acs.jpcb.8b10792}, author = {Ngo, Son Tung and Philippe Derreumaux and Vu, Van V} } @article {2018|2129, title = {Probing the quality control mechanism of the twin-arginine translocase with folding variants of a -designed heme protein.}, journal = {J Biol Chem}, volume = {293}, year = {2018}, month = {2018 05 04}, pages = {6672-6681}, abstract = {

Protein transport across the cytoplasmic membrane of bacterial cells is mediated by either the general secretion (Sec) system or the twin-arginine translocase (Tat). The Tat machinery exports folded and cofactor-containing proteins from the cytoplasm to the periplasm by using the transmembrane proton motive force as a source of energy. The Tat apparatus apparently senses the folded state of its protein substrates, a quality-control mechanism that prevents premature export of nascent unfolded or misfolded polypeptides, but its mechanistic basis has not yet been determined. Here, we investigated the innate ability of the model Tat system to recognize and translocate -designed protein substrates with experimentally determined differences in the extent of folding. Water-soluble, four-helix bundle maquette proteins were engineered to bind two, one, or no heme cofactors, resulting in a concomitant reduction in the extent of their folding, assessed with temperature-dependent CD spectroscopy and one-dimensional H NMR spectroscopy. Fusion of the archetypal N-terminal Tat signal peptide of the trimethylamine--oxide (TMAO) reductase (TorA) to the N terminus of the protein maquettes was sufficient for the Tat system to recognize them as substrates. The clear correlation between the level of Tat-dependent export and the degree of heme -induced folding of the maquette protein suggested that the membrane-bound Tat machinery can sense the extent of folding and conformational flexibility of its substrates. We propose that these artificial proteins are ideal substrates for future investigations of the Tat system\&$\#$39;s quality-control mechanism.

}, keywords = {Amino Acid Sequence, Bacterial Proteins, Circular Dichroism, Escherichia coli, Escherichia coli Proteins, Heme-Binding Proteins, Hemeproteins, Membrane Transport Proteins, Methylamines, Models, Molecular, Oxidoreductases, N-Demethylating, Periplasm, Protein Folding, Protein Sorting Signals, Protein Stability, Protein Transport, Proton Magnetic Resonance Spectroscopy, Substrate Specificity, Temperature}, issn = {1083-351X}, doi = {10.1074/jbc.RA117.000880}, author = {Sutherland, George A and Grayson, Katie J and Adams, Nathan B P and Mermans, Daphne M J and Jones, Alexander S and Robertson, Angus J and Auman, Dirk B and Brindley, Amanda A and Sterpone, Fabio and Tuffery, Pierre and Philippe Derreumaux and Dutton, P Leslie and Robinson, Colin and Hitchcock, Andrew and Hunter, C Neil} } @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 {2016|1733, title = {PEP-FOLD3: faster denovo structure prediction for linear peptides in solution and in complex}, journal = {Nucleic Acids Res.}, volume = {44}, number = {W1}, year = {2016}, pages = {W449-W454}, abstract = {Structure determination of linear peptides of 5-50 amino acids in aqueous solution and interacting with proteins is a key aspect in structural biology. PEP-FOLD3 is a novel computational framework, that allows both (i) de novo free or biased prediction for linear peptides between 5 and 50 amino acids, and (ii) the generation of native-like conformations of peptides interacting with a protein when the interaction site is known in advance. PEP-FOLD3 is fast, and usually returns solutions in a few minutes. Testing PEP-FOLD3 on 56 peptides in aqueous solution led to experimental-like conformations for 80\% of the targets. Using a benchmark of 61 peptide-protein targets starting from the unbound form of the protein receptor, PEP-FOLD3 was able to generate peptide poses deviating on average by 3.3 angstrom from the experimental conformation and return a native-like pose in the first 10 clusters for 52\% of the targets. PEP-FOLD3 is available at http://bioserv.rpbs.univ-paris-diderot.fr/services/PEP-FOLD3.}, issn = {0305-1048}, doi = {10.1093/nar/gkw329}, author = {Lamiable, Alexis and Thevenet, Pierre and Rey, Julien and Vavrusa, Marek and Philippe Derreumaux and Pierre Tuffery} } @article {2016|1744, title = {Picosecond infrared laser-induced all-atom nonequilibrium molecular dynamics simulation of dissociation of viruses}, journal = {Phys. Chem. Chem. Phys.}, volume = {18}, number = {17}, year = {2016}, month = {may}, pages = {11951{\textendash}11958}, abstract = {Since the discovery of the plant pathogen tobacco mosaic virus as the first viral entity in the late 1800s, viruses traditionally have been mainly thought of as pathogens for disease-resistances. However, viruses have recently been exploited as nanoplatforms with applications in biomedicine and materials science. To this aim, a large majority of current methods and tools have been developed to improve the physical stability of viral particles, which may be critical to the extreme physical or chemical conditions that viruses may encounter during purification, fabrication processes, storage and use. However, considerably fewer studies are devoted to developing efficient methods to degrade or recycle such enhanced stability biomaterials. With this in mind, we carry out all-atom nonequilibriummolecular dynamics simulation, inspired by the recently developed mid-infrared free-electron laser pulse technology, to dissociate viruses. Adopting the poliovirus as a representative example, we find that the primary step in the dissociation process is due to the strong resonance between the amide I vibrational modes of the virus and the tuned laser frequencies. This process is determined by a balance between the formation and dissociation of the protein shell, reflecting the highly plasticity of the virus. Furthermore, our method should provide a feasible approach to simulate viruses, which is otherwise too expensive for conventional equilibrium all-atom simulations of such very large systems. Our work shows a proof of concept which may open a new, efficient way to cleave or to recycle virus-based materials, provide an extremely valuable tool for elucidating mechanical aspects of viruses, and may well play an important role in future fighting against virus-related diseases.}, issn = {1463-9076}, doi = {10.1039/c5cp07711g}, author = {Viet Hoang Man and Van-Oanh, Nguyen-Thi and Philippe Derreumaux and Li, Mai Suan and Roland, Christopher and Sagui, Celeste and Phuong Hoang Nguyen} } @article {2015|1449, title = {{P}redicting and exploring complex nucleic acids architectures through a coarse-grained model}, journal = {J. Biomol. Struct. Dyn.}, volume = {33 Suppl 1}, year = {2015}, pages = {30{\textendash}31}, author = {Cragnolini, T. and Doutreligne, S. and Marc Baaden and Philippe Derreumaux and Pasquali, S.} } @article {2015|1705, title = {Picosecond dissociation of amyloid fibrils with infrared laser: A nonequilibrium simulation study}, journal = {J. Chem. Phys.}, volume = {143}, number = {15}, year = {2015}, month = {oct}, pages = {155101}, doi = {10.1063/1.4933207}, author = {Man Hoang Viet and Philippe Derreumaux and Mai Suan Li and Roland, Christopher and Sagui, Celeste and Phuong Hoang Nguyen} } @article {2015|1745, title = {Picosecond melting of peptide nanotubes using an infrared laser: a nonequilibrium simulation study}, journal = {Phys. Chem. Chem. Phys.}, volume = {17}, number = {41}, year = {2015}, pages = {27275{\textendash}27280}, doi = {10.1039/c5cp04401d}, author = {Viet, Man Hoang and Phan Minh Truong and Philippe Derreumaux and Li, Mai Suan and Roland, Christopher and Sagui, Celeste and Phuong Hoang Nguyen} } @article {2015|1701, title = {Predicting and exploring complex nucleic acids architectures through a coarse-grained model}, journal = {Journal of Biomolecular Structure \& Dynamics}, volume = {33}, year = {2015}, pages = {30{\textendash}31}, doi = {10.1080/07391102.2015.1032593}, author = {Cragnolini, T. and Doutreligne, S. and Marc Baaden and Philippe Derreumaux and Pasquali, S.} } @article {2015|1709, title = {Protein Simulations in Fluids: Coupling the OPEP Coarse-Grained Force Field with Hydrodynamics}, journal = {J. Chem. Theory Comput.}, volume = {11}, number = {4}, year = {2015}, month = {apr}, pages = {1843{\textendash}1853}, doi = {10.1021/ct501015h}, author = {Fabio Sterpone and Philippe Derreumaux and Melchionna, Simone} } @article {2012|1944, title = {PEP-FOLD: an updated de novo structure prediction server for both linear and disulfide bonded cyclic peptides}, journal = {Nucleic Acids Res.}, volume = {40}, number = {W1}, year = {2012}, month = {jul}, pages = {W288-W293}, doi = {10.1093/nar/gks419}, author = {Thevenet, Pierre and Shen, Yimin and Maupetit, Julien and Guyon, Frederic and Philippe Derreumaux and Pierre Tuffery} } @article {2009|1734, title = {PEP-FOLD: an online resource for de novo peptide structure prediction}, journal = {Nucleic Acids Res.}, volume = {37}, year = {2009}, month = {jul}, pages = {W498-W503}, doi = {10.1093/nar/gkp323}, author = {Maupetit, Julien and Philippe Derreumaux and Pierre Tuffery} } @article {2009|1942, title = {PEP-FOLD: an online resource for de novo peptide structure prediction.}, journal = {Nucleic Acids Res.}, volume = {37}, number = {Web Server issue}, year = {2009}, month = {jul}, pages = {W498{\textendash}W503}, keywords = {Algorithms, Internet, Models, Molecular, Peptides, Protein, Protein Conformation, Reproducibility of Results, Sequence Analysis, Software, User-Computer Interface}, doi = {10.1093/nar/gkp323}, author = {Julien Maupetit and Philippe Derreumaux and Pierre Tuffery} } @article {2007|1954, title = {{P}robing amyloid fibril formation of the {N}{F}{G}{A}{I}{L} peptide by computer simulations}, journal = {J. Chem. Phys.}, volume = {126}, number = {6}, year = {2007}, month = {feb}, pages = {065101}, doi = {10.1063/1.2435358}, author = {Melquiond, A. and Gelly, J.C. and Mousseau, N. and Philippe Derreumaux} } @conference {2006, title = {PHYS 4-Applications of activated methods to proteins and materials science}, booktitle = {Abstracts of Papers of the American Chemical Society}, volume = {232}, year = {2006}, author = {Mousseau, Normand and Barkema, Gerard T. and Chubynsky, Mykyta V. and Philippe Derreumaux and El-Mellouhi, Fedwa and Vocks, Henk} } @article {2004|1994, title = {Pathway complexity of Alzheimer{\textquoteright}s beta-amyloid A beta(16-22) peptide assembly}, journal = {Structure}, volume = {12}, number = {7}, year = {2004}, month = {jul}, pages = {1245{\textendash}1255}, doi = {10.1016/j.str.2004.04.018}, author = {Santini, S and Wei, GH and Mousseau, N and Philippe Derreumaux} } @article {2000|1899, title = {Predicting helical hairpins from sequences by Monte Carlo simulations}, journal = {J. Comput. Chem.}, volume = {21}, number = {7}, year = {2000}, month = {may}, pages = {582{\textendash}589}, doi = {10.1002/(SICI)1096-987X(200005)21:7<582}, author = {Philippe Derreumaux} }