@article {2023, title = {Conformational and mechanical stability of the isolated large subunit of membrane-bound [NiFe]-hydrogenase from Cupriavidus necator}, journal = {Frontiers in Microbiology}, volume = {13}, year = {2023}, abstract = {

Comprising at least a bipartite architecture, the large subunit of [NiFe]-hydrogenase harbors the catalytic nickel\–iron site while the small subunit houses an array of electron-transferring Fe-S clusters. Recently, some [NiFe]-hydrogenase large subunits have been isolated showing an intact and redox active catalytic cofactor. In this computational study we have investigated one of these metalloproteins, namely the large subunit HoxG of the membrane-bound hydrogenase from Cupriavidus necator (CnMBH), targeting its conformational and mechanical stability using molecular modelling and long all-atom Gaussian accelerated molecular dynamics (GaMD). Our simulations predict that isolated HoxG is stable in aqueous solution and preserves a large portion of its mechanical properties, but loses rigidity in regions around the active site, in contrast to the MBH heterodimer. Inspired by biochemical data showing dimerization of the HoxG protein and IR measurements revealing an increased stability of the [NiFe] cofactor in protein preparations with higher dimer content, corresponding simulations of homodimeric forms were also undertaken. While the monomeric subunit contains several flexible regions, our data predicts a regained rigidity in homodimer models. Furthermore, we computed the electrostatic properties of models obtained by enhanced sampling with GaMD, which displays a significant amount of positive charge at the protein surface, especially in solvent-exposed former dimer interfaces. These data offer novel insights on the way the [NiFe] core is protected from de-assembly and provide hints for enzyme anchoring to surfaces, which is essential information for further investigations on these minimal enzymes.

}, issn = {1664-302X}, doi = {10.3389/fmicb.2022.1073315}, url = {https://www.frontiersin.org/articles/10.3389/fmicb.2022.1073315}, author = {Dragelj, Jovan and Karafoulidi-Retsou, Chara and Katz, Sagie and Lenz, Oliver and Zebger, Ingo and Caserta, Giorgio and S Sacquin-Mora and Mroginski, Maria Andrea} } @article {2019|2061, title = {Coarse-grain simulations on NMR conformational ensembles highlight functional residues in proteins.}, journal = {J R Soc Interface}, volume = {16}, year = {2019}, month = {2019 Jul 26}, pages = {20190075}, abstract = {

Dynamics are a key feature of protein function, and this is especially true of gating residues, which occupy cavity or tunnel lining positions in the protein structure, and will reversibly switch between open and closed conformations in order to control the diffusion of small molecules within a protein\&$\#$39;s internal matrix. Earlier work on globins and hydrogenases have shown that these gating residues can be detected using a multiscale scheme combining all-atom classic molecular dynamics simulations and coarse-grain calculations of the resulting conformational ensemble mechanical properties. Here, we show that the structural variations observed in the conformational ensembles produced by NMR spectroscopy experiments are sufficient to induce noticeable mechanical changes in a protein, which in turn can be used to identify residues important for function and forming a mechanical nucleus in the protein core. This new approach, which combines experimental data and rapid coarse-grain calculations and no longer needs to resort to time-consuming all-atom simulations, was successfully applied to five different protein families.

}, issn = {1742-5662}, doi = {10.1098/rsif.2019.0075}, author = {S Sacquin-Mora} } @article {2019|2060, title = {Conformational Stability Adaptation of a Double-Stranded RNA-Binding Domain to Transfer RNA Ligand.}, journal = {Biochemistry}, volume = {58}, year = {2019}, month = {2019 May 21}, pages = {2463-2473}, abstract = {

The double-stranded RNA-binding domain (dsRBD) is a broadly distributed domain among RNA-maturing enzymes. Although this domain recognizes dsRNA\&$\#$39;s structures via a conserved canonical structure adopting an α-βββ-α topology, several dsRBDs can accommodate discrete structural extensions expanding further their functional repertoire. How these structural elements engage cooperative communications with the canonical structure and how they contribute to the dsRBD\&$\#$39;s overall folding are poorly understood. Here, we addressed these issues using the dsRBD of human dihydrouridine synthase-2 (hDus2) (hDus2-dsRBD) as a model. This dsRBD harbors N- and C-terminal extensions, the former being directly involved in the recognition of tRNA substrate of hDus2. These extensions engage residues that form a long-range hydrophobic network (LHN) outside the RNA-binding interface. We show by coarse-grain Brownian dynamics that the Nt-extension and its residues F359 and Y364 rigidify the major folding nucleus of the canonical structure via an indirect effect. hDus2-dsRBD unfolds following a two-state cooperative model, whereas both F359A and Y364A mutants, designed to destabilize this LHN, unfold irreversibly. Structural and computational analyses show that these mutants are unstable due to an increase in the dynamics of the two extensions favoring solvent exposure of α2-helix and weakening the main folding nucleus rigidity. This LHN appears essential for maintaining a thermodynamic stability of the overall system and eventually a functional conformation for tRNA recognition. Altogether, our findings suggest that functional adaptability of extended dsRBDs is promoted by a cooperative hydrophobic coupling between the extensions acting as effectors and the folding nucleus of the canonical structure.

}, issn = {1520-4995}, doi = {10.1021/acs.biochem.9b00111}, author = {Bou-Nader, Charles and Pecqueur, Ludovic and Barraud, Pierre and Fontecave, Marc and Tisn{\'e}, Carine and S Sacquin-Mora and Hamdane, Djemel} } @article {2018|2046, title = {Controlling Redox Enzyme Orientation at Planar Electrodes}, journal = {Catalysts}, volume = {8}, year = {2018}, abstract = {

Redox enzymes, which catalyze reactions involving electron transfers in living organisms, are very promising components of biotechnological devices, and can be envisioned for sensing applications as well as for energy conversion. In this context, one of the most significant challenges is to achieve efficient direct electron transfer by tunneling between enzymes and conductive surfaces. Based on various examples of bioelectrochemical studies described in the recent literature, this review discusses the issue of enzyme immobilization at planar electrode interfaces. The fundamental importance of controlling enzyme orientation, how to obtain such orientation, and how it can be verified experimentally or by modeling are the three main directions explored. Since redox enzymes are sizable proteins with anisotropic properties, achieving their functional immobilization requires a specific and controlled orientation on the electrode surface. All the factors influenced by this orientation are described, ranging from electronic conductivity to efficiency of substrate supply. The specificities of the enzymatic molecule, surface properties, and dipole moment, which in turn influence the orientation, are introduced. Various ways of ensuring functional immobilization through tuning of both the enzyme and the electrode surface are then described. Finally, the review deals with analytical techniques that have enabled characterization and quantification of successful achievement of the desired orientation. The rich contributions of electrochemistry, spectroscopy (especially infrared spectroscopy), modeling, and microscopy are featured, along with their limitations.

}, issn = {2073-4344}, doi = {10.3390/catal8050192}, url = {http://www.mdpi.com/2073-4344/8/5/192}, author = {Hitaishi, Vivek Pratap and Clement, Romain and Bourassin, Nicolas and Marc Baaden and de Poulpiquet, Anne and S Sacquin-Mora and Ciaccafava, Alexandre and Lojou, Elisabeth} } @mastersthesis {2011|1574, title = {Coarse-grain models for proteins: Mechanical properties and interactions}, year = {2011}, note = {HDR d{\'e}livr{\'e}e par l{\textquoteright}UFR Sciences du Vivant}, month = {dec}, school = {Universit{\'e} Paris-Diderot - Paris VII}, type = {phdHabilitation {\`a} diriger des recherches}, keywords = {Computational biology, docking, elastic networks, interactions prot{\'e}iques, m{\'e}canique des prot{\'e}ines, Mod{\'e}lisation mol{\'e}culaire, protein interactions, protein mechanics, r{\'e}seau {\'e}lastique}, url = {https://tel.archives-ouvertes.fr/tel-00652917}, author = {S Sacquin-Mora} } @article {2009|1442, title = {{C}harge {R}ecombination {K}inetics and {P}rotein {D}ynamics in {W}ild {T}ype and {C}arotenoid-less {B}acterial {R}eaction {C}enters: {S}tudies in {T}rehalose {G}lasses}, journal = {J. Phys. Chem. B}, volume = {113}, year = {2009}, month = {jul}, pages = {10389{\textendash}1398}, author = {Francia, F. and Malferrari, M. and S Sacquin-Mora and Venturoli, G.} } @book {2009|1567, title = {Coarse-graining protein mechanics}, volume = {Coarse-Graining of Condensed Phase and Biomolecular Systems}, year = {2009}, publisher = {Taylor and Francis}, organization = {Taylor and Francis}, author = {R Lavery and S Sacquin-Mora}, editor = {G. Voth} }