A docking analysis of the statistical physics of protein-protein recognition.

International audienceWe describe protein-protein recognition within the frame of the random energy model of statistical physics. We simulate, by docking the component proteins, the process of association of two proteins that form a complex. We obtain the energy spectrum of a set of protein-protein complexes of known three-dimensional structure by performing docking in random orientations and scoring the models thus generated. We use a coarse protein representation where each amino acid residue is replaced by its Voronoï cell, and derive a scoring function by applying the evolutionary learning program ROGER to a set of parameters measured on that representation. Taking the scores of the docking models to be interaction energies, we obtain energy spectra for the complexes and fit them to a Gaussian distribution, from which we derive physical parameters such as a glass transition temperature and a specificity transition temperature

Une nouvelle fonction de score pour l'amarrage protéine-protéine fondée sur les diagrammes de Voronoï

International audienceDans cet article, nous décrivons l'interaction protéine-protéine dans le cadre du modèle de l'énergie stochastique (Random Energy Model) de la physique statistique. Nous simulons en amarrant les deux protéines partenaires, le processus d'association de deux protéines formant un complexe. Nous obtenons les spectres d'énergie d'un jeu de complexes protéine-protéine de structure tridimensionnelle connue en effectuant l'amarrage dans des orientations aléatoires et en calculant un score pour les complexes modèles ainsi générés. Nous utilisons une représentation très simplifiée de la structure où chaque acide aminé est remplacé par sa cellule de Voronoï, et nous appliquons le programme d'apprentissage par algorithme génétique ROGER à un ensemble de paramètres mesurés sur cette représentation, afin de dériver une fonction de score appropriée. En considérant les scores obtenus comme des énergies d'interaction, nous obtenons le spectre d'énergie de chaque complexe. Il s'approche d'une distribution gaussienne qui nous permet de calculer des paramètres physiques comme la température de transition vitreuse et la température de transition spécifique du système

DiMoVo: a Voronoi tessellation-based method for discriminating crystallographic and biological protein-protein interactions.

International audienceMOTIVATION: Knowledge of the oligomeric state of a protein is often essential for understanding its function and mechanism. Within a protein crystal, each protein monomer is in contact with many others, forming many small interfaces and a few larger ones that are biologically significant if the protein is a homodimer in solution, but not if the protein is monomeric. Telling such 'crystal dimers' from real ones remains a difficult task. RESULTS: It has already been demonstrated that the interfaces of native and non-native protein-protein complexes can be distinguished using a combination of parameters computed with a method on the Voronoi tessellation. We show in this article that the same parameters highlight significant differences between the interfaces of biological and crystal dimers. Using these parameters as descriptors in machine learning methods leads to accurate classification of specific and non-specific protein-protein interfaces. AVAILABILITY: Software is available at http://fifi.ibbmc.u-psud.fr/DiMoVo

Lithium poisoning: Is determination of the red blood cell lithium concentration useful?

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Poisoning with gold potassium cyanide and other metallic cyanides in a jeweler

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The rotavirus nonstructural protein NSP5 coordinates a [2Fe-2S] iron-sulfur cluster that modulates interaction to RNA.

International audienceDuring rotavirus infection, replication and packaging of the viral genome occur in viral factories, termed viroplasms. The viral nonstructural protein NSP5 is a major building block of viroplasms; it recruits the viral polymerase VP1, the core protein VP2, and the ATPase NSP2 inside the viroplasm to form the viral replication complex. Here we report that NSP5 is a unique viral metalloprotein that coordinates a [2Fe-2S] iron-sulfur cluster as demonstrated by the metal and labile sulfide contents, UV-visible light absorption, and electron paramagnetic resonance. Point mutations in NSP5 allowed us to identify C171 and C174, arranged in a CXC motif, as essential residues for cluster coordination. When coexpressed with NSP2, an NSP5 mutant devoid of the iron-sulfur cluster still forms viroplasm-like structures. The cluster is therefore neither involved in the interaction with NSP2 nor in the formation of viroplasm-like structures and thus presumably in viroplasm formation. Finally, we show using microscale thermophoresis that the iron-sulfur cluster modulates the affinity of NSP5 for single-stranded RNA. Because the cluster is near the binding sites of both the polymerase VP1 and the ATPase NSP2, we anticipate that this cluster is crucial for NSP5 functions, in either packaging or replication of the viral genome

Résine biosourcée pour une composition cosmétique et son procédé de fabrication

La présente invention concerne une résine polyester biosourcée comprenant un mélange de diols et de polyacides, son procédé de préparation ainsi qu’une composition filmogène et un vernis à ongles comprenant ladite résine. La résine polyester peut notamment être utile en tant que liant dans un vernis à ongles

Extensive striatal, cortical, and white matter brain MRI abnormalities in Wilson disease

International audienceA 16-year-old boy presented with progressive dysarthria and gait and behavior disorders. The diagnosis of Wilson disease was made, based on Kayser-Fleischer rings, hypocupremia, hypoceruloplasminemia, and increased 24-hour urinary copper, and confirmed by molecular analysis (homozygous state, p.[Glu1382*]; [Glu1382*]). Brain MRI demonstrated diffuse bilateral cortical and subcortical abnormalities (figure). Chelator therapy (D-penicillamine) produced partial improvement, although the patient developed epileptic seizures, presumably due to the cortical involvement. Wilson disease with extensive cortical-subcortical lesions is rare,1,2 but should be considered as a possible etiology of diffuse leukoencephalopathy with cystic evolution