Molecular Dynamcis analysis

^{by Robert Greil and Cedric Landerer}

Wildtype

First of all, we checked the resulting file with gmxcheck.

• gmxcheck -f ref_md.tpr.xtc

Result

Reading frame       0 time    0.000   
# Atoms  68601
Precision 0.001 (nm)
Last frame       2000 time 10000.000   

Item        #frames Timestep (ps)
Step          2001    5
Time          2001    5
Lambda           0
Coords        2001    5
Velocities       0
Forces           0
Box           2001    5

The Simulation toked 6h33:50 ans the simulation speed was 36.564 ns/day. So, to reach 1 second of simulation, we had to wait around 75061 years. But this is a bit to long for this Project, so we just used the results we got. The potential energy was fluctuating about -9.185e+05 kJ/mol with a range of about 0.15e+04 kJ/mol. These information are given in the different log-files provided by the simulation.

Figure 1: Motion of the wild-type protein, Cartoon representation

Figure 2: Motion of the wild-type protein

To create the images, we saved each frame in PyMol<ref>The PyMOL Molecular Graphics System, Version 1.2r3pre, Schrödinger, LLC</ref> as an image, which we converted into gif format by for file in *.png; do convert "$file" "$(basename $file .png).gif"; done. Than we were able to use gifsicle to create an animated gif with the command gifsicle *.gif -loop.

As one can see in Figure 1 and Figure 2, we have mostly a motion in space. The motion within the protein, like it is shown by the normal mode analysis is not identifiable. There is no movement of the beta-sheet or helical region against each other.

Quality assurance

Convergence of energy terms

• g_energy -f ref_md.tpr.edr -o xvg/xxxx.xvg

Temperature

Figure 3: Temperature over time of the molecular dynamics simulation of the wild-type protein

Energy                      Average   Err.Est.       RMSD  Tot-Drift 
-------------------------------------------------------------------------------
Temperature                 297.942     0.0055    1.11471  0.0143589  (K)

Pressure

Figure 4: Pressure over time of the molecular dynamics simulation of the wild-type protein

Figure 3 shows the temperature over the simulation time. The Energy fluctuates between 294K (20.85°C) and 302k (28.85°C) around a mean of about 298K (24.85°C). So, the protein is simulated in a temperature range at which a hypothermia would be the consequence.

Energy                      Average   Err.Est.       RMSD  Tot-Drift
-------------------------------------------------------------------------------
Pressure                   0.995939      0.014     83.256  0.0113633  (bar)

Energy

Figure 5: Energy over time of the molecular dynamics simulation of the wild-type protein

Energy                      Average   Err.Est.       RMSD  Tot-Drift
-------------------------------------------------------------------------------
Potential                   -919346         21    889.917   -54.8929  (kJ/mol)
Kinetic En.                  164147          3    614.133    7.91086  (kJ/mol)
Total Energy                -755199         19    1096.12   -46.9806  (kJ/mol)

Volume

Figure 6: Volume over time of the molecular dynamics simulation of the wild-type protein

Energy                      Average   Err.Est.       RMSD  Tot-Drift
-------------------------------------------------------------------------------
Volume                      694.068      0.012   0.512013 0.00522608  (nm^3)

Density

Figure 7: Densety over time of the molecular dynamics simulation of the wild-type protein

Energy                      Average   Err.Est.       RMSD  Tot-Drift
-------------------------------------------------------------------------------
Density                     999.461      0.018   0.737307 -0.00750088  (kg/m^3)

Box

Figure 8: Box size in X,Y and Z direction over time of the molecular dynamics simulation of the wild-type protein. The X and Y values are equal over time.

Energy                      Average   Err.Est.       RMSD  Tot-Drift
-------------------------------------------------------------------------------
Box-X                       9.93815    5.8e-05 0.00244379 2.49479e-05  (nm)
Box-Y                       9.93815    5.8e-05 0.00244379 2.49479e-05  (nm)
Box-Z                       7.02734    4.1e-05 0.00172803 1.76268e-05  (nm)

Mutation 8a [C282Y]

still waiting to finish // LRZ won't do anything because of LRZ cluster update

Mutation 8b [C282S]

still waiting to finish // LRZ won't do anything because of LRZ cluster update

References

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