ptraj can be used for more than just folding trajectories. it should work
fine for clustering your small molecules.
On Tue, Dec 8, 2009 at 9:48 AM, Andrew Voronkov <drugdesign.yandex.ru>wrote:
> Btw, ptraj can be used only for analysis of protein trajectories?
>
> One of the problems in computer assisted drug esign is proper conformations
> prediction for the small molecule compounds.
> I wonder if it s possible to cluster small molecule conformations resulted
> from let s say 10-50 ps trajectory and us it for database preparation.
> For example 100 000 DB preparation then should take only 1-5 microseconds
> and for each molecule will request much lower times than for the protein.
> But in this case the water influence on small molecule conformation will be
> included which may be futher used for virtual screening purposes for example
>
> Best regards,
> Andrew
>
> 06.12.09, 10:23, "Thomas Cheatham" <tec3.utah.edu>:
>
> >
> >  > Yes, larger motions have some influence as far as the binding site is
> in
> >  > the interface of homodimer and there are some little oscillations in
> >  > monomers distance. But I actually also want to optimize somehow the
> >  > number of clusters.
> >
> >  You can read our paper on clustering MD trajectories in JCTC (Shao et
> al.)
> >  and from this you will see that the metrics are not always so clear.  In
> >  practice, my general path is to look at a 2D RMSd plot and count the
> >  number of big squares on the diagonal.  Alternatively, I look at the
> >  cluster counts (i.e. how many frames in each cluster) which is reported
> at
> >  the bottom on the *.txt file...  i.e. below it looks like there are 4
> >  major clusters (1, 2, 5, 6) based on the count; the graphical time
> course
> >  suggests that the clusters are not revisited much...
> >
> >  #Clustering: divide 258425 points into 7 clusters
> >  #Cluster    0: has  6647 points, occurence 0.026
> >  #Cluster    1: has 133732 points, occurence 0.517
> >  #Cluster    2: has 58864 points, occurence 0.228
> >  #Cluster    3: has   243 points, occurence 0.001
> >  #Cluster    4: has  1110 points, occurence 0.004
> >  #Cluster    5: has 32013 points, occurence 0.124
> >  #Cluster    6: has 25816 points, occurence 0.100
> >  #Cluster    0   .  ... ..                      . . . 54.1 .  ....
> >  #Cluster    1   9XX999X99XXX999999X9X9X98.   . .....54.. ..   ..
> >  #Cluster    2      .        ...... . . .1999999799994...
> >  #Cluster    3   .                        ....... .
> >  #Cluster    4                                 .1.
> >  #Cluster    5                                . ..    .5781...29997
> >  #Cluster    6                                          ..89997 ..2
> >
> >  -- tec3
> >
> >
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Received on Tue Dec 08 2009 - 07:30:02 PST