in silico
Phase 1 : In Silico Validation
- Objectif
- To computationally verify the feasibility of the proposed mechanotransduction mechanism, specifically: (1) the aptamer-MMP-9 binding energy and force generation, (2) the force required to unfold the mechanosensitive peptide, and (3) the rigidity of the dsDNA spacer under load. This phase aims to “kill” the hypothesis cheaply and quickly if any of these core assumptions fail.
- Coût estimé
- €1,500-2,000 (HPC core-hours, software licenses if not already owned)
- Durée estimée
- 6-8 weeks
- Critères de réussite
- Aptamer-MMP-9 binding force · ≥ 10 pN (from steered MD, average of 3 replicates) · (Steered MD force-extension curve; peak force at rupture)
- Peptide unfolding force · ≤ 10 pN for wild-type; ≥ 20 pN for mutant (from steered MD) · (Steered MD force-extension curve; force at which the peptide unfolds (RMSD > 0.3 nm))
- dsDNA spacer buckling probability · < 5% under 10 pN axial load + 1 pN lateral perturbation · (FEA: ratio of simulations where lateral displacement > 0.5 nm)
- Crosslink density reduction in CG model · ≥ 40% reduction in crosslink density (Δρ) upon simulated MMP-9 binding · (LAMMPS: number of intact crosslinks before and after force application)
- On continue si
- All four success criteria are met (binding force ≥10 pN, peptide unfolds at ≤10 pN, spacer buckling <5%, crosslink density reduction ≥40%).
- On arrête si
- Any two of the four success criteria fail (e.g., binding force <5 pN, peptide unfolding force >15 pN, buckling >20%, crosslink density reduction <20%).
- On réoriente si
- Only one criterion fails: e.g., if the dsDNA spacer buckles, redesign with a longer spacer (40 bp) or a stiffer linker (e.g., DNA origami). If the peptide unfolding force is too high, redesign with a weaker β-sheet or a different mechanosensitive domain (e.g., a coiled-coil).
- Risques
- MD simulations may not capture the full conformational dynamics of the aptamer-MMP-9 complex (e.g., induced fit vs. conformational selection).Probabilité : mediumParade : Use enhanced sampling techniques (metadynamics) and validate with experimental smFRET data from literature.
- The CG model of the hydrogel may be too coarse to capture the viscoelastic relaxation of the polymer network.Probabilité : mediumParade : Use a finer-grained model (e.g., MARTINI with elastic networks) and compare with known rheological data for PEG hydrogels.
- The FEA model of dsDNA may not account for sequence-dependent flexibility or salt effects.Probabilité : lowParade : Use a more detailed model (e.g., oxDNA) for the dsDNA spacer if buckling is borderline.