Laboratoire de Biochimie Théorique
Présentation
The Laboratory of Theoretical Biochemistry (LBT) is one of five laboratories within Institut de Biologie Physico-Chimique (IBPC) in Paris.
LBT belongs to the French national research agency CNRS through its Institute of Chemistry, and is associated with Paris Diderot University. The laboratory was created at IBPC in 1958 as Laboratoire de Biochimie Théorique. Our field is theoretical and computational biochemistry, at the interface between biology, chemistry, physics, and computing.
Our strategic objectives are twofold: invent simulation algorithms to reproduce and predict physical properties of biomolecules either in vitro or in the cell, and understand the molecular or conformational factors responsible for the biological functions of living systems, and diseases. The equilibrium between these two aspects is the key point of the laboratory policy.
LBT is organized as a team of independent researchers with complementary interests and domains of expertise, both in method development and in biophysical, biochemical, and biomedical applications. Advances in each of these domains emerge from the association of different sets of researchers around individual projects.
Thèmes de recherche
Les axes de recherches du LBT se concentrent sur les développements méthodologiques et algorithmiques pour l’étude de la structure, la dynamique, la mécanique et les interactions des macromolécules biologiques.
Les objectifs sont donc d'utiliser les ordinateurs pour ouvrir des fenêtres vers le monde moléculaire, en aidant à comprendre les facteurs qui sous-tendent des faits expérimentaux, et en prédisant les propriétés et le comportement des molécules biologiques.
Equipes de recherche
Directeur : Marc Baaden
[hal-02924964] Side-chain rotamer transitions at protein-protein interfaces
Date: 26 juil 2021 - 15:10
Desc: [...]
[hal-03294641] Between two walls: Modeling the adsorption behavior of β-glucosidase A on bare and SAM-functionalised gold surfaces
Date: 24 juil 2021 - 04:13
Desc: Abstract The efficient immobilization of enzymes on surfaces remains a complex but central issue in the biomaterials field, which requires us to understand this process at the atomic level. Using a multi-scale approach combining all-atom molecular dynamics and coarse-grain Brownian dynamics simulations, we investigated the adsorption behavior of β-glucosidase A (βGA) on bare and SAM-functionalized gold surfaces. We monitored the enzyme position and orientation during the MD trajectories, and measured the contacts it forms with both surfaces. While the adsorption process has little impact on the protein conformation, it can nonetheless perturb its mechanical properties and catalytic activity. Our results show that compared to the SAM-functionalized surface, the adsorption of βGA on bare gold is more stable, but also less specific, and more likely to disrupt the enzyme’s function. This observation emphasizes the fact that the structural organization of proteins at the solid interface is a keypoint when designing devices based on enzyme immobilization, as one must find an acceptable stability-activity trade-off. TOC image
[hal-03065754] Moving pictures: Reassessing docking experiments with a dynamic view of protein interfaces
Date: 21 juil 2021 - 17:59
Desc: The modeling of protein assemblies on the atomic level remains a central issue in structural biology, as protein interactions play a key role in numerous cellular processes. This problem is traditionally addressed using docking tools, where the quality of the models that are produced is based on their similarity to a single reference experimental structure. However, this approach using a static reference does not take into account the dynamic quality of the protein interface. Here, we used all-atom classical Molecular Dynamics simulations to investigate the stability of the interface for three complexes that previously served as targets in the CAPRI competition, and for each one of these targets, ten models distributed over the High, Medium and Acceptable categories. To assess the quality of these models from a dynamic perspective, we set up new criteria which take into account the stability of the reference protein interface. We show that, when the protein interfaces are allowed to evolve along time, the original ranking based on the static CAPRI criteria no longer holds as over 50% of the docking models undergo a category change (either toward a better or a lower group) when reassessing their quality using dynamic information.
[inria-00637848] Community-Wide Assessment of Protein-Interface Modeling Suggests Improvements to Design Methodology.
Date: 20 juil 2021 - 05:07
Desc: The CAPRI (Critical Assessment of Predicted Interactions) and CASP (Critical Assessment of protein Structure Prediction) experiments have demonstrated the power of community-wide tests of methodology in assessing the current state of the art and spurring progress in the very challenging areas of protein docking and structure prediction. We sought to bring the power of community-wide experiments to bear on a very challenging protein design problem that provides a complementary but equally fundamental test of current understanding of protein-binding thermodynamics. We have generated a number of designed protein-protein interfaces with very favorable computed binding energies but which do not appear to be formed in experiments, suggesting that there may be important physical chemistry missing in the energy calculations. A total of 28 research groups took up the challenge of determining what is missing: we provided structures of 87 designed complexes and 120 naturally occurring complexes and asked participants to identify energetic contributions and/or structural features that distinguish between the two sets. The community found that electrostatics and solvation terms partially distinguish the designs from the natural complexes, largely due to the nonpolar character of the designed interactions. Beyond this polarity difference, the community found that the designed binding surfaces were, on average, structurally less embedded in the designed monomers, suggesting that backbone conformational rigidity at the designed surface is important for realization of the designed function. These results can be used to improve computational design strategies, but there is still much to be learned; for example, one designed complex, which does form in experiments, was classified by all metrics as a nonbinder.
[hal-01018071] Innovative interactive flexible docking method for multi-scale reconstruction elucidates dystrophin molecular assembly
Date: 13 juil 2021 - 15:17
Desc: At present, our molecular knowledge of dystrophin, the protein encoded by the DMD gene and mutated in myopathy patients, remains limited. To get around the absence of its atomic structure, we have developed an innovative interactive docking method based on the BioSpring software in combination with Small-angle X-ray Scattering (SAXS) data. BioSpring allows interactive handling of biological macromolecules thanks to an augmented Elastic Network Model (aENM) that combines the spring network with non-bonded terms between atoms or pseudo-atoms. This approach can be used for building molecular assemblies even on a desktop or a laptop computer thanks to code optimizations including parallel computing and GPU programming. By combining atomistic and coarse-grained models, the approach significantly simplifies the set-up of multi-scale scenarios. BioSpring is remarkably efficient for the preparation of numeric simulations or for the design of biomolecular models integrating qualitative experimental data restraints. The combination of this program and SAXS allowed us to propose the first high-resolution models of the filamentous central domain of dystrophin, covering repeats 11 to 17. Low-resolution interactive docking experiments driven by a potential grid enabled us to propose how dystrophin may associate with F-actin and nNOS. This information provides an insight into medically relevant discoveries to come.
Autres contacts
Institut de Biologie Physico-Chimique (IBPC)
13, rue Pierre et Marie Curie
75252 PARIS CEDEX 05
