[chimerax-users] how to vizualise hydrogen bonds between ligand and back-bone of protein?

Mon Mar 21 09:09:38 PDT 2022

Hello,
We can't figure out the reason for the "missing" H-bond unless you send us the file with the ligand and receptor atomic coordinates, the same ones shown in the image..  If you didn't want to share it with the whole chimerax-users list but you are willing to share it with the ChimeraX team, you can send it to just my individual e-mail address.  However, if you need to keep it completely private we understand.
Best,
Elaine
-----
Elaine C. Meng, Ph.D.                       
UCSF Chimera(X) team
Department of Pharmaceutical Chemistry
University of California, San Francisco

> On Mar 21, 2022, at 2:28 AM, Enrico Martinez <jmsstarlight at gmail.com> wrote:
> 
> Hello Elaine
> Many thanks for these kind suggestions!
> In fact this back-bone H-bond has been validated by X-ray data
> (observed in several structures of my protein) and then by my docking
> studies. Please find enclosed the picture of this interaction: as we
> may see it is located on the relatively short distance between the O
> atom of the ligand and the HN of the backbone of the Glu residue. I
> believe it has to match both default slope criteria....
> 
> Regarding my command, actually I used it with batch version of
> chimeraX (in the script) so the goal was not to display the
> interactions but rather to save it directly into the log file:
> 
> # calculate h-bonds between first 10 models from multi-model pdb file
> hbonds #1.1-10&protein restrict #1.1-10&ligand coordsets false
> interModel false makePseudobonds false log true intraRes false
> saveFile log_hbondsALL.log
> 
> It produces a log with the correct H-bonds with the exemption of the
> interaction shown on the screenshot (which is always detected by other
> programs...)
> With best regards,
> Enrico
> 
> вт, 15 мар. 2022 г. в 17:28, Elaine Meng <meng at cgl.ucsf.edu>:
>> 
>> I see you are not displaying the H-bonds in your command anyway, but another thing that confuses some people is that even though the H-bond is found (i.e. it is counted and listed in the Log) it is not displayed because the atoms are not displayed.
>> 
>> In other words, if you are using the display to judge whether the H-bond is found you would need to use the "hbond" command options:
>> 
>> makePseudobond true reveal true
>> 
>> <https://rbvi.ucsf.edu/chimerax/docs/user/commands/hbonds.html#options>
>> 
>> Elaine
>> 
>> 
>>> On Mar 15, 2022, at 9:20 AM, Elaine Meng via ChimeraX-users <chimerax-users at cgl.ucsf.edu> wrote:
>>> 
>>> Those "slop" values are tolerances, not the scope (cutoff):  i.e. they are added to increase the allowed ranges of values for the specific types of atoms.  A distSlop of 0.8 does not mean distance cutoff 0.8, it means 0.8 + the strict cutoff (which might be 3.0 or something like that, for a total of 3.8).
>>> 
>>> Reasons to not find the H-bond:
>>> 
>>> - maybe your atom specification is wrong... in fact I have no idea what the "}" are in your command, they look wrong.  However, that would probably cause an error message and you would not get any H-bonds at all.  Since you are getting some H-bonds maybe that is not the problem.
>>> 
>>> - maybe those types of atoms are not considered by the H-bond detection.  I.e. it does not consider C to be an H-bonding type of atom.
>>> 
>>> - maybe it is because the H-bond geometry is very poor, you still need to increase the slop values even more to find it.
>>> 
>>> However: We believe that Chimera and ChimeraX provide high-quality H-bond detection with the default parameters (or with small increases in the distSlop and angleSlop), so it is unclear why you think your other program finding the H-bond is more correct.  Maybe it should not be considered an H-bond.
>>> 
>>> Best,
>>> Elaine
>>> -----
>>> Elaine C. Meng, Ph.D.
>>> UCSF Chimera(X) team
>>> Department of Pharmaceutical Chemistry
>>> University of California, San Francisco
>>> 
>>>> On Mar 15, 2022, at 8:17 AM, Enrico Martinez <jmsstarlight at gmail.com> wrote:
>>>> 
>>>> Hello again!
>>>> I've just make a test for several docking poses and I confirm that the
>>>> hydrogen bond between ligand and backbone atoms never could be
>>>> detected by chimera using
>>>> hbonds #1.1-14}&protein restrict #1.1-14}&ligand coordsets false
>>>> interModel false makePseudobonds false log true intraRes false
>>>> saveFile log.txt
>>>> 
>>>> I tried to increase significantly the distance scope to 0.8 and the
>>>> angle scope to 40 but the interactions could not be detected. Could it
>>>> be the problem with the command that I am using ?
>>>> Many thanks in advance!
>>>> 
>>>> пн, 14 мар. 2022 г. в 15:38, Enrico Martinez <jmsstarlight at gmail.com>:
>>>>> 
>>>>> Thank you very much, Elaine!
>>>>> Indeed, I found that these two options influence the results.
>>>>> Cheers,
>>>>> Enrico
>>>>> 
>>>>> чт, 10 мар. 2022 г. в 19:46, Elaine Meng <meng at cgl.ucsf.edu>:
>>>>>> 
>>>>>> Hello,
>>>>>> Specifications like "#1.1&protein" already include the backbone atoms -- they are part of the protein.
>>>>>> 
>>>>>> <https://rbvi.ucsf.edu/chimerax/docs/user/commands/atomspec.html#builtin>
>>>>>> 
>>>>>> Maybe the H-bond(s) that you think should be found are less favorable (longer distance and/or poorer angle).  In that case you could try using larger values than the defaults with the "distSlop" and/or "angleSlop" options of "hbonds" to make detection more permissive.
>>>>>> 
>>>>>> <https://rbvi.ucsf.edu/chimerax/docs/user/commands/hbonds.html#options>
>>>>>> 
>>>>>> I hope this helps,
>>>>>> Elaine
>>>>>> -----
>>>>>> Elaine C. Meng, Ph.D.
>>>>>> UCSF Chimera(X) team
>>>>>> Department of Pharmaceutical Chemistry
>>>>>> University of California, San Francisco
>>>>>> 
>>>>>>> On Mar 10, 2022, at 3:28 AM, Enrico Martinez via ChimeraX-users <chimerax-users at cgl.ucsf.edu> wrote:
>>>>>>> 
>>>>>>> Dear ChimeraX users!
>>>>>>> I am using the following command to calculate and save in the log
>>>>>>> information regarding hydrogen bonds based on the consideration of
>>>>>>> multi-frame pdb of the complex
>>>>>>> 
>>>>>>> # calculate hydrogen bonds for the first 14 frames of pdb
>>>>>>> hbonds #1.1-14}&protein restrict #1.1-14}&ligand coordsets false
>>>>>>> interModel false makePseudobonds false log true intraRes false
>>>>>>> saveFile log.txt
>>>>>>> 
>>>>>>> which gives me something like this:
>>>>>>> structure_name:
>>>>>>> 18 H-bonds
>>>>>>> H-bonds (donor, acceptor, hydrogen, D..A dist, D-H..A dist):
>>>>>>> #1.1/? ASN 142 ND2    #1.1/A UNL 1 N        #1.1/? ASN 142 2HD2   3.313  2.522
>>>>>>> #1.1/? SER 144 N      #1.1/A UNL 1 O        #1.1/? SER 144 H      2.953  2.224
>>>>>>> #1.1/A UNL 1 O        #1.1/? LEU 141 O      #1.1/A UNL 1 H        2.753  1.877
>>>>>>> #1.2/? ASN 142 ND2    #1.2/A UNL 1 N        #1.2/? ASN 142 2HD2   3.240  2.429
>>>>>>> #1.2/A UNL 1 O        #1.2/? HIS 163 NE2    #1.2/A UNL 1 H        3.317  2.389
>>>>>>> #1.3/? SER 144 N      #1.3/A UNL 1 O        #1.3/? SER 144 H      3.005  2.272
>>>>>>> #1.3/A UNL 1 O        #1.3/? LEU 141 O      #1.3/A UNL 1 H        2.738  2.098
>>>>>>> #1.3/A UNL 1 O        #1.3/? SER 144 OG     #1.3/A UNL 1 H        3.054  2.250
>>>>>>> #1.6/A UNL 1 O        #1.6/? HIS 163 NE2    #1.6/A UNL 1 H        3.172  2.528
>>>>>>> #1.7/? CYS 145 SG     #1.7/A UNL 1 O        #1.7/? CYS 145 HG     3.828  2.949
>>>>>>> #1.7/A UNL 1 O        #1.7/? LEU 141 O      #1.7/A UNL 1 H        3.201  2.393
>>>>>>> #1.8/? GLY 143 N      #1.8/A UNL 1 O        #1.8/? GLY 143 H      3.060  2.238
>>>>>>> #1.8/? HIS 163 NE2    #1.8/A UNL 1 O       no hydrogen            3.084  N/A
>>>>>>> #1.9/? GLN 189 NE2    #1.9/A UNL 1 O        #1.9/? GLN 189 1HE2   3.148  2.139
>>>>>>> #1.10/? GLN 189 NE2   #1.10/A UNL 1 O       #1.10/? GLN 189 1HE2  2.941  2.289
>>>>>>> #1.10/A UNL 1 O       #1.10/? GLN 189 OE1   #1.10/A UNL 1 H       2.985  2.213
>>>>>>> #1.11/? GLN 189 NE2   #1.11/A UNL 1 O       #1.11/? GLN 189 1HE2  2.803  1.910
>>>>>>> #1.14/? ASN 142 ND2   #1.14/A UNL 1 O       #1.14/? ASN 142 2HD2  3.199  2.369
>>>>>>> -----------------------------------------------------------------------------
>>>>>>> 
>>>>>>> I noticed that in the log there is always information regarding
>>>>>>> interactions between the ligand and the side chains of the protein but
>>>>>>> nothing regarding hydrogen bonds involved backbone of the protein
>>>>>>> (Which is confirmed by X-ray data for my complex). for the test I used
>>>>>>> py at ol to visualise h-bonds and may see in the 12th frame the hydrogen
>>>>>>> bond involved backbone of the protein.. How could I modify my script
>>>>>>> to consider additional hydrogen bonds involving backbone atoms ?
>>>>>>> Thank you very much in advance!
>>>>>>> Cheers
>>>>>>> Enrico
>>>>>> 
>>>> 
>>> 
>>> 
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>> 
> <test_hbonds-min.png>