Team:EPF-Lausanne/Modeling

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(Molecular dynamics: a little theory)
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==Molecular dynamics: a little theory==
==Molecular dynamics: a little theory==
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Molecular dynamics simulation consists of the numerical, step-by-step, solution of the classical equations of motion. For this purpose we need to be able to calculate the forces acting on the atoms, and these are usually derived from a potential energy. This potential energy can be divided into:
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Molecular dynamics simulation consists of the numerical, step-by-step, solution of the classical equations of motion. For this purpose we need to be able to calculate the forces acting on the atoms, and these are usually derived from a potential energy.  
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This potential energy can be divided into:
===The non-bonded interactions:===   
===The non-bonded interactions:===   
*The ''Lennard-Jones potential'' is the most commonly used form, with two parameters: σ, the diameter, and ε, the well depth. It takes into account the Van der Waals forces. It represents the non-bonded forces and the total potential energy can be calculated from the sum of energy contributions between pairs of atoms.  
*The ''Lennard-Jones potential'' is the most commonly used form, with two parameters: σ, the diameter, and ε, the well depth. It takes into account the Van der Waals forces. It represents the non-bonded forces and the total potential energy can be calculated from the sum of energy contributions between pairs of atoms.  
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[[Media:Introduction_to_molecular_Dynamics_Simulation.pdf‎ | Introduction to Molecular Dynamics Simulation - Michael P. Allen]]
[[Media:Introduction_to_molecular_Dynamics_Simulation.pdf‎ | Introduction to Molecular Dynamics Simulation - Michael P. Allen]]
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==Steps==
==Steps==

Revision as of 08:09, 21 September 2009

                               


Modeling overview



Protein domain of interest

Our protein of interest is LOVTAP. This protein was sythetically engineered by Sosnick group. It is a fusion protein between a LOV domain (Avena Sativa phototropin 1) and the E. Coli tryptophan repressor. This protein undergoes changes under light activation as shown by Sosnick et al, in fact when the protein is activated by light it binds DNA and inversely. For more information about LOVTAP protein please click here.

Goal

Starting material

Both LOV domain crystallography files were obtained from RCSB:

Light activated LOV domain
Dark LOV domain

These crystallographies were done by Halavaty et al..

Molecular dynamics: a little theory

Molecular dynamics simulation consists of the numerical, step-by-step, solution of the classical equations of motion. For this purpose we need to be able to calculate the forces acting on the atoms, and these are usually derived from a potential energy.

         Click here to show/hide

Steps

Minimization

Equilibration

Analysis and validation

Simulation

Atom movement analysis

References

Analysis methodology

Results

To do

- Model allosteric interactions between LOVTAP & TrpR
What will be done:
- Model of LOVTAP in dark phase
- Model of LOVTAP in light phase
- Characterize how the J-alpha helix changes
- Model structural changes that enhance the switch feature of LOVTAP e.g. in dark phase: really weak interaction between LOVTAP and the corresponding DNA sequence, in light phase: strong binding of LOVTAP on DNA.
- Between Light state and Dark State
- RMS between light state and dark state
- length between the two arms N C
- only cytochrome with interactions in light state and dark state


To envisage


- Molecular mutational assay