@article {2022|2156, title = {Building Biological Relevance Into Integrative Modelling of Macromolecular Assemblies}, journal = {Frontiers in Molecular Biosciences}, volume = {9}, year = {2022}, pages = {826136}, abstract = {

Recent advances in structural biophysics and integrative modelling methods now allow us to decipher the structures of large macromolecular assemblies. Understanding the dynamics and mechanisms involved in their biological function requires rigorous integration of all available data. We have developed a complete modelling pipeline that includes analyses to extract biologically significant information by consistently combining automated and interactive human-guided steps. We illustrate this idea with two examples. First, we describe the ryanodine receptor, an ion channel that controls ion flux across the cell membrane through transitions between open and closed states. The conformational changes associated with the transitions are small compared to the considerable system size of the receptor; it is challenging to consistently track these states with the available cryo-EM structures. The second example involves homologous recombination, in which long filaments of a recombinase protein and DNA catalyse the exchange of homologous DNA strands to reliably repair DNA double-strand breaks. The nucleoprotein filament reaction intermediates in this process are short-lived and heterogeneous, making their structures particularly elusive. The pipeline we describe, which incorporates experimental and theoretical knowledge combined with state-of-the-art interactive and immersive modelling tools, can help overcome these challenges. In both examples, we point to new insights into biological processes that arise from such interdisciplinary approaches.

}, issn = {2296-889X}, doi = {10.3389/fmolb.2022.826136}, url = {https://www.frontiersin.org/article/10.3389/fmolb.2022.826136}, author = {Molza, Anne-Elisabeth and Westermaier, Yvonne and Moutte, Magali and Ducrot, Pierre and Danilowicz, Claudia and Godoy-Carter, Veronica and Prentiss, Mara and Robert, Charles H. and Marc Baaden and Pr{\'e}vost, Chantal} } @article {2018|2093, title = {Dystrophin{\textquoteright}s central domain forms a complex filament that becomes disorganized by in-frame deletions.}, journal = {J Biol Chem}, volume = {293}, year = {2018}, month = {2018 05 04}, pages = {6637-6646}, abstract = {

Dystrophin, encoded by the gene, is critical for maintaining plasma membrane integrity during muscle contraction events. Mutations in the gene disrupting the reading frame prevent dystrophin production and result in severe Duchenne muscular dystrophy (DMD); in-frame internal deletions allow production of partly functional internally deleted dystrophin and result in less severe Becker muscular dystrophy (BMD). Many known BMD deletions occur in dystrophin\&$\#$39;s central domain, generally considered to be a monotonous rod-shaped domain based on the knowledge of spectrin family proteins. However, the effects caused by these deletions, ranging from asymptomatic to severe BMD, argue against the central domain serving only as a featureless scaffold. We undertook structural studies combining small-angle X-ray scattering and molecular modeling in an effort to uncover the structure of the central domain, as dystrophin has been refractory to characterization. We show that this domain appears to be a tortuous and complex filament that is profoundly disorganized by the most severe BMD deletion (loss of exons 45-47). Despite the preservation of large parts of the binding site for neuronal nitric oxide synthase (nNOS) in this deletion, computational approaches failed to recreate the association of dystrophin with nNOS. This observation is in agreement with a strong decrease of nNOS immunolocalization in muscle biopsies, a parameter related to the severity of BMD phenotypes. The structural description of the whole dystrophin central domain we present here is a first necessary step to improve the design of microdystrophin constructs toward the goal of a successful gene therapy for DMD.

}, keywords = {Binding Sites, Dystrophin, Exons, Gene Deletion, Humans, Molecular Docking Simulation, Muscular Dystrophy, Duchenne, Nitric Oxide Synthase Type I, Protein Domains, Reading Frames, Scattering, Small Angle, Solutions, X-Ray Diffraction}, issn = {1083-351X}, doi = {10.1074/jbc.M117.809798}, author = {Delalande, Olivier and Molza, Anne-Elisabeth and Dos Santos Morais, Raphael and Ch{\'e}ron, Ang{\'e}lique and Pollet, {\'E}meline and Raguenes-Nicol, C{\'e}line and Tascon, Christophe and Giudice, Emmanuel and Guilbaud, Marine and Nicolas, Aur{\'e}lie and Bondon, Arnaud and Leturcq, France and Nicolas F{\'e}rey and Marc Baaden and Perez, Javier and Roblin, Pierre and Pi{\'e}tri-Rouxel, France and Hubert, Jean-Fran{\c c}ois and Czjzek, Mirjam and Le Rumeur, Elisabeth} }