SLIDE 1 A Path Planning Approach for Computing A Path Planning Approach for Computing Large Large-
- Amplitude Motions of Flexible Molecules
Amplitude Motions of Flexible Molecules
Juan Cortés & Thierry Siméon
MOVIE Workshop, Toulouse, 7-8/01/2005
SLIDE 2
MOVIE Workshop, Toulouse, 7-8/01/2005
Context : Computational Biology Context : Computational Biology
( Interaction )
Bio-informatics Molecular modeling Flexibility
SLIDE 3 MOVIE Workshop, Toulouse, 7-8/01/2005
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Protein Flexibility Protein Flexibility
Local
Low
Side chains Plasticity Loop motions Domain motions
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SLIDE 4
MOVIE Workshop, Toulouse, 7-8/01/2005
Difficulty : Complexity of Potential Energy Difficulty : Complexity of Potential Energy
Electrostatic Other Lennard Jones Torsion Bending Stretching
: H bonds, hydrophobic interactions ,…
Bonded terms Non-bonded terms
SLIDE 5
MOVIE Workshop, Toulouse, 7-8/01/2005
Potential Energy Potential Energy → → Geometric Constraints Geometric Constraints
Electrostatic Other Lennard Jones Torsion Bending Stretching Bonded terms Non-bonded terms
SLIDE 6 MOVIE Workshop, Toulouse, 7-8/01/2005
A Two A Two-
Stage Approach
- Exploration under geometric
constraints Motion planning algorithms
Filtering
Classical molecular modeling methods New methods ?
SLIDE 7 MOVIE Workshop, Toulouse, 7-8/01/2005
Geometric Tools : Collision Detection Geometric Tools : Collision Detection
Challenge: Self-collisions of highly articulated mechanisms BioCD
[Robotics’05 (submitted)]
- Tailored for protein models
- Dual structure (kd-trees)
- first level
- second level
- Many d.o.f. change simultaneously
- Performance: Hundreds of tests/second
SLIDE 8 MOVIE Workshop, Toulouse, 7-8/01/2005
Geometric Tools : Conformational Sampling Geometric Tools : Conformational Sampling
Kinematic loop closure → → → → RLG [ICRA’02]
loop 1 loop 2 loop 3
→ → → → qa
→ → → qp active subchain(s) passive subchain non-redundant mechanism
- planar : 3 d.o.f.
- spatial : 6 d.o.f.
Mechanical system decomposition
SLIDE 9
MOVIE Workshop, Toulouse, 7-8/01/2005
Geometric Tools : Conformational Sampling Geometric Tools : Conformational Sampling
Active variables ← ← ← ← guided sampling Passive variables ← ← ← ← inverse kinematics
Kinematic loop closure → → → → RLG [ICRA’02]
SLIDE 10 MOVIE Workshop, Toulouse, 7-8/01/2005
Geometric Tools : Conformational Sampling Geometric Tools : Conformational Sampling
begin end rigid unit dihedral angle
- Main chain (backbone)
- Side chains
Protein loop [J Comput Chem 04]
SLIDE 11 MOVIE Workshop, Toulouse, 7-8/01/2005
Geometric Tools : Conformational Sampling Geometric Tools : Conformational Sampling
begin end rigid unit dihedral angle
- passive subchain
- general 6R IK + BioCD
- Main chain (backbone)
- active subchain
- RLG & BioCD
- Side chains
Protein loop [J Comput Chem 04]
SLIDE 12
MOVIE Workshop, Toulouse, 7-8/01/2005
Geometric Tools : Conformational Exploration Geometric Tools : Conformational Exploration
Incremental search → → → → RRT [LaValle and Kuffner, 2001] DD-RRT [ICRA’05]
Good performance in very constrained search space
SLIDE 13
MOVIE Workshop, Toulouse, 7-8/01/2005
Applications : Analysis of Protein Loop Mobility Applications : Analysis of Protein Loop Mobility
Xylanase
from Thermobacillus xylanilyticus
Flexible loop : 69 d.o.f.
SLIDE 14
MOVIE Workshop, Toulouse, 7-8/01/2005
Applications : Analysis of Protein Loop Mobility Applications : Analysis of Protein Loop Mobility
Conformational sampling
Two-step simulated annealing → Several days of work Geometric approach → Up to few minutes Energetically feasible conformation from geometrically feasible one → RMSD = 0.65 Å
Hydrogen bond network
SLIDE 15 MOVIE Workshop, Toulouse, 7-8/01/2005
Applications : Analysis of Protein Loop Mobility Applications : Analysis of Protein Loop Mobility
Xylanase
from Thermobacillus xylanilyticus
Exploration with RRT
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Mutated Xylanase
(deletion 111, 121)
Prediction for directed mutagenesis
Conformational exploration
SLIDE 16 MOVIE Workshop, Toulouse, 7-8/01/2005
Deep active site (17Å)
Applications : Applications : Ligand Ligand-
Protein Accessibility Pathways Accessibility Pathways
Bulkholderia cepacia Lipase Ligand and side-chain flexibility : 45 d.o.f.
Prediction of enzymatic enantioselectivity
R enantiomer S enantiomer
SLIDE 17 MOVIE Workshop, Toulouse, 7-8/01/2005
Applications : Applications : Ligand Ligand-
Protein Accessibility Pathways Accessibility Pathways
Ligand: (R)-ph(Br)Et Ligand: (S)-ph(Br)Et
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Prediction of enzymatic enantioselectivity
SLIDE 18 MOVIE Workshop, Toulouse, 7-8/01/2005
Applications : Applications : Ligand Ligand-
Protein Accessibility Pathways Accessibility Pathways
Similar trajectories and energetic profiles
Correlation of results
Computing time = 3 days Computing time = 30 minutes (including energy minimization) Pseudo-molecular dynamics Two-stage approach
energy-based approach
4,5 5,5 6,5 7,5 8,5 9,5 10,5
distance ()
R S
two-stage approach
4,5 5,5 6,5 7,5 8,5 9,5 10,5
distance ()
R S
SLIDE 19 MOVIE Workshop, Toulouse, 7-8/01/2005
Applications : Applications : Ligand Ligand-
Protein Accessibility Pathways Accessibility Pathways
Computing time ratio ~ enantioselectivity
Correlation of results
SLIDE 20 MOVIE Workshop, Toulouse, 7-8/01/2005
Future Work Future Work
- Automatic identification of flexible regions
→ Normal mode analysis
Ligand-protein Protein-protein
- Integrating loop motions in the analysis of interactions
SLIDE 21 MOVIE Workshop, Toulouse, 7-8/01/2005
A Path Planning Approach for Computing A Path Planning Approach for Computing Large Large-
- Amplitude Motions of Flexible Molecules
Amplitude Motions of Flexible Molecules
Juan Cortés Thierry Siméon jcortes@laas.fr nic@laas.fr
SLIDE 22
MOVIE Workshop, Toulouse, 7-8/01/2005