Hi everyone!

I tried doing H-bond analysis using g_hbond on a solute dissolved in water. The 
solute has hydroxyl groups. In an attempt to analyze water-bridges formed thru 
H-bonds, I noticed that g_hbond does not seem to give consistent results. As 
previously discussed in this list, I am taking advantage of the hbmap file to 
parse out the Hbond trajectories needed to count the water bridges. A possible 
water-bridge type is one in which the hydrogen of a water molecule is shared by 
two different oxygens of the solute. Since there are two H's per water molecule 
I expected two sets of indices for each H. This is what I did.

1. To simplify parsing the resulting HBMap, I intended to create an HBMap.xpm 
for a water and a pair of hydroxyl residues from the solute. For a shared H 
above, that would be (O solute...Hwater...O solute). Creating a set of indices 
for this configuration was successful upon running (g_hbond .... -hbn), but 
only for one set of Hwater. g_hbond was not able to create another set for the 
other H of water. (Note though that g_hbond was able to correctly identify both 
Hs of water as donors). g_hbond correctly counted H-bonds for this set and 
produced a reliable HBMap.xpm 

2. Another set of indices was manually created for the other H. However, the 
hbnum.xvg of this set is unreliable compared with the above and the values 
shoot to 1000 times expected h-bond counts. Please note that the HBMap.xpm for 
the hydrogen bonds between water and the solute only lists one H for each water 
as if ignoring the other H (in cases that there should be two). 

Your advice/ideas/comments is very much welcome and very much needed.


Thanks,

Bernard
-- 
gmx-users mailing list    gmx-users@gromacs.org
http://lists.gromacs.org/mailman/listinfo/gmx-users
Please search the archive at 
http://www.gromacs.org/Support/Mailing_Lists/Search before posting!
Please don't post (un)subscribe requests to the list. Use the 
www interface or send it to gmx-users-requ...@gromacs.org.
Can't post? Read http://www.gromacs.org/Support/Mailing_Lists

Reply via email to