Re: [ccp4bb] missing covalent bond between asparagine and N-acetylglucosamine using coot carbohydrate module and phenix.refine

2021-06-24 Thread Hinrichs, Winfried
Dear Jiang, 



to draw a line or a dotted line is a question of graphics and
definitions of the specific software and has nothing to do with the
specific nature of a chemical bond. 
"link" defines in your case only an additional chemical bond that is
not defined for the common polypeptide chain. 



best, 

Winfried Hinrichs

--
Dr. rer. nat. Winfried Hinrichs
Professor and Chair of Biochemistry, Emeritus

University of Greifswald
Institute for Biochemistry
Felix-Hausdorff-Str. 4
D-17487 Greifswald, Germany

E-mail winfried.hinri...@uni-greifswald.de

http://orcid.org/-0002-0435-4565

--




Am Donnerstag, den 24-06-2021 um 13:40 schrieb jiang:


Hello guys,     I am a little bit confused. Since the
polysaccharide is attached to asparagine via covalent bond. I am not
sure what “link” means anyway.  Does it mean some other chemical
bonds? Or not chemical bond at all.
      As you can see from the book link below, the nitrogen atom
 from the N-glycosylation site has covalent bond with only one
hydrogen atom. The bond is referred to as glycosidic bond.
 https://www.ncbi.nlm.nih.gov/books/NBK22521/
     
Thank you,
Best,
Jiang
Sent from my iPhone



On Jun 24, 2021, at 12:35 AM, Folmer Fredslund  wrote:






Dear Jiang


As Paul Emsley was already kind to point out:


Coot draws solid lines for bonds between neighbouring monomers in a
polymer.
The bond between NAG and ASN is not such a bond - it is a link.
Links are drawn as dashed lines in Coot.



So, a dashed line is simply how such a bond is represented in Coot.
It's not a bug in the software.


I'm not quite sure why you want the bond to be represented with a
solid line instead of a dashed line. 
It makes no difference whatsoever on the validity of the model.


Best wishes
Folmer Fredslund










ons. 23. jun. 2021 01.23 skrev Jiang Xu :



Hello David,    I used the "Make Link" under the "Modeling..." tab
to create the bond. It worked, but the bond displayed is still a
dashed line, not a solid line as shown below. I still don't know how
to use phenix to add a solid bond between the two atoms.  So, is it a
bug in the software or I didn't do it correctly? 


Thank you,
Best,
Jiang


On Tue, Jun 22, 2021 at 3:48 PM Jiang Xu  wrote:



Hello David,    I tried to rebuild the polysaccharide chain using
the N-link add NAG, NAG, BMA method, saved the model and ran
phenix.refine without checking the "automatically add hydrogens to the
model". I also double checked to make sure that the "Link
carbohydrates to protein and other carbohydrates" within the
"Automatic Linking Options" was checked. The "Carbohydrate bond
cutoff" is the set to the default value of 1.99, which I didn't
change.  However, after running phenix.refine, the bond disappeared
again. As shown below, on the left is the input model, on the right is
the refined output. You can see that the bond is gone and the distance
between C1 of NAG and the Nitrogen atom of the amine group is 1.42 A.
So Could anything else cause the problem?




Thank you,
Best,
Jiang


On Mon, Jun 21, 2021 at 11:11 PM David Briggs  wrote:



   Hi Jiang Xu,

 

 (Phenixbb added as I suspect this is Phenix not coot that has caused
your issue)


 Did you check the "add hydrogens" button in Phenix.refine? Sometimes
this can erroneously add a second H to the ND of glycosylated Asn
residues. (I assume this is because bond distances in the input PDB
file fall outside Phenix's definitions of an Asn-NAG link).
 

 If the second H is added, this breaks the refinement of the Asn-NAG
bond.


 My work around is to run "Ready Set" to add hydrogens as a separate
job, and then manually inspect and correct the Asn residues as
necessary before running Phenix.refine and _not_ checking the "add
hydrogens" box.
 

 I hope this fixes your problem.
 

 Good luck,
 

 Dave
 

   --

 Dr David C. Briggs

 Senior Laboratory Research Scientist

 Signalling and Structural Biology Lab

 The Francis Crick Institute

 London, UK

 ==

 about.me/david_briggs [1]



-
 From: CCP4 bulletin board  on behalf of Jiang Xu 
Sent: Tuesday, June 22, 2021 6:47:36 AM
To: CCP4BB@JISCMAIL.AC.UK 
Subject: [ccp4bb] missing covalent bond between asparagine and
N-acetylglucosamine using coot carbohydrate module and phenix.refine
 

   External Sender:  Use caution.
   Hello guys,     I have a problem building and refining an xtal
structure. My protein has a N-glycosylation site and I want to add
N-acetylglucosamine and manose to my protein structure. I used Coot's
carbohydrate module and let Coot automatically build the sugar chain
to the electron density. It worked pretty well, but I noticed that
the bond between the amine group of asparagine and the C1 of
N-acetylglucosa

Re: [ccp4bb] missing covalent bond between asparagine and N-

2021-06-24 Thread Rezaul Karim
Hi Jiang,I can understand why you are confused. I think I faced such case once. 
But Paul & Folmer's description is correct, that's the way coot works. Here is 
the way I solved it.In coot, after linking save the pdb without 
hydrogen.(Optional, if Phenix says it needs cif file - do readyset)Refine that 
pdb in Phenix without hydrogen.Then check it in coot & pymol. Even coot shows 
dotted lines, pymol will show a solid bond😀!Hope it helps!

Best,Reza

Md Rezaul Karim, Ph.D.
Postdoctoral Research Fellow
Department of Drug Discovery
H. Lee Moffitt Cancer Center and Research Institute
Tampa, FL 33612
Email: reza.ka...@moffitt.org, rez...@usf.edu
Phone: (813) 745 4673 ext. 5462
https://orcid.org/-0002-0424-127X 
 
  On Thu, Jun 24, 2021 at 7:40 AM, jiang wrote:   Hello 
guys,     I am a little bit confused. Since the polysaccharide is attached to 
asparagine via covalent bond. I am not sure what “link” means anyway.  Does it 
mean some other chemical bonds? Or not chemical bond at all.      As you can 
see from the book link below, the nitrogen atom  from the N-glycosylation site 
has covalent bond with only one hydrogen atom. The bond is referred to as 
glycosidic bond. https://www.ncbi.nlm.nih.gov/books/NBK22521/     
Thank you,Best,Jiang
Sent from my iPhone

On Jun 24, 2021, at 12:35 AM, Folmer Fredslund  wrote:



Dear Jiang
As Paul Emsley was already kind to point out:
Coot draws solid lines for bonds between neighbouring monomers in a polymer.
The bond between NAG and ASN is not such a bond - it is a link.
Links are drawn as dashed lines in Coot.

So, a dashed line is simply how such a bond is represented in Coot. It's not a 
bug in the software.
I'm not quite sure why you want the bond to be represented with a solid line 
instead of a dashed line. It makes no difference whatsoever on the validity of 
the model.
Best wishesFolmer Fredslund





ons. 23. jun. 2021 01.23 skrev Jiang Xu :

Hello David,    I used the "Make Link" under the "Modeling..." tab to create 
the bond. It worked, but the bond displayed is still a dashed line, not a solid 
line as shown below. I still don't know how to use phenix to add a solid bond 
between the two atoms.  So, is it a bug in the software or I didn't do it 
correctly? 
Thank you,Best,Jiang
On Tue, Jun 22, 2021 at 3:48 PM Jiang Xu  wrote:

Hello David,    I tried to rebuild the polysaccharide chain using the N-link 
add NAG, NAG, BMA method, saved the model and ran phenix.refine without 
checking the "automatically add hydrogens to the model". I also double checked 
to make sure that the "Link carbohydrates to protein and other carbohydrates" 
within the "Automatic Linking Options" was checked. The "Carbohydrate bond 
cutoff" is the set to the default value of 1.99, which I didn't change.  
However, after running phenix.refine, the bond disappeared again. As shown 
below, on the left is the input model, on the right is the refined output. You 
can see that the bond is gone and the distance between C1 of NAG and the 
Nitrogen atom of the amine group is 1.42 A. So Could anything else cause the 
problem?
Thank you,Best,Jiang
On Mon, Jun 21, 2021 at 11:11 PM David Briggs  wrote:

Hi Jiang Xu,

(Phenixbb added as I suspect this is Phenix not coot that has caused your issue)

Did you check the "add hydrogens" button in Phenix.refine? Sometimes this can 
erroneously add a second H to the ND of glycosylated Asn residues. (I assume 
this is because bond distances in the input PDB file fall outside Phenix's 
definitions of an Asn-NAG link).
If the second H is added, this breaks the refinement of the Asn-NAG bond.

My work around is to run "Ready Set" to add hydrogens as a separate job, and 
then manually inspect and correct the Asn residues as necessary before running 
Phenix.refine and _not_ checking the "add hydrogens" box.
I hope this fixes your problem.
Good luck,
Dave
--
Dr David C. Briggs
Senior Laboratory Research Scientist
Signalling and Structural Biology Lab
The Francis Crick Institute
London, UK
==
about.me/david_briggs
From: CCP4 bulletin board  on behalf of Jiang Xu 

Sent: Tuesday, June 22, 2021 6:47:36 AM
To: CCP4BB@JISCMAIL.AC.UK 
Subject: [ccp4bb] missing covalent bond between asparagine and 
N-acetylglucosamine using coot carbohydrate module and phenix.refine  External 
Sender: Use caution. Hello guys,    I have a problem building and refining an 
xtal structure. My protein has a N-glycosylation site and I want to add 
N-acetylglucosamine and manose to my protein structure. I used Coot's 
carbohydrate module and let Coot automatically build the sugar chain to the 
electron density. It worked pretty well, but I noticed that the bond between 
the amine group of asparagine and the C1 of N-acetylglucosamine is depicted as 
a dashed line, rather than a solid line in Coot. After refinement of

Re: [ccp4bb] missing covalent bond between asparagine and N-acetylglucosamine using coot carbohydrate module and phenix.refine

2021-06-24 Thread jiang
Hello guys,
 I am a little bit confused. Since the polysaccharide is attached to 
asparagine via covalent bond. I am not sure what “link” means anyway.  Does it 
mean some other chemical bonds? Or not chemical bond at all.
  As you can see from the book link below, the nitrogen atom  from the 
N-glycosylation site has covalent bond with only one hydrogen atom. The bond is 
referred to as glycosidic bond.
 https://www.ncbi.nlm.nih.gov/books/NBK22521/
 
Thank you,
Best,
Jiang
Sent from my iPhone

> On Jun 24, 2021, at 12:35 AM, Folmer Fredslund  wrote:
> 
> Dear Jiang
> 
> As Paul Emsley was already kind to point out:
> 
> Coot draws solid lines for bonds between neighbouring monomers in a polymer.
> The bond between NAG and ASN is not such a bond - it is a link.
> Links are drawn as dashed lines in Coot.
> 
> 
> So, a dashed line is simply how such a bond is represented in Coot. It's not 
> a bug in the software.
> 
> I'm not quite sure why you want the bond to be represented with a solid line 
> instead of a dashed line. 
> It makes no difference whatsoever on the validity of the model.
> 
> Best wishes
> Folmer Fredslund
> 
> 
> 
> 
> 
> 
> ons. 23. jun. 2021 01.23 skrev Jiang Xu :
>> Hello David,
>> I used the "Make Link" under the "Modeling..." tab to create the bond. 
>> It worked, but the bond displayed is still a dashed line, not a solid line 
>> as shown below. I still don't know how to use phenix to add a solid bond 
>> between the two atoms.  So, is it a bug in the software or I didn't do it 
>> correctly? 
>> 
>> 
>> Thank you,
>> Best,
>> Jiang
>> 
>>> On Tue, Jun 22, 2021 at 3:48 PM Jiang Xu  wrote:
>>> Hello David,
>>> I tried to rebuild the polysaccharide chain using the N-link add NAG, 
>>> NAG, BMA method, saved the model and ran phenix.refine without checking the 
>>> "automatically add hydrogens to the model". I also double checked to make 
>>> sure that the "Link carbohydrates to protein and other carbohydrates" 
>>> within the "Automatic Linking Options" was checked. The "Carbohydrate bond 
>>> cutoff" is the set to the default value of 1.99, which I didn't change.  
>>> However, after running phenix.refine, the bond disappeared again. As shown 
>>> below, on the left is the input model, on the right is the refined output. 
>>> You can see that the bond is gone and the distance between C1 of NAG and 
>>> the Nitrogen atom of the amine group is 1.42 A. So Could anything else 
>>> cause the problem?
>>> 
>>> 
>>> 
>>> Thank you,
>>> Best,
>>> Jiang
>>> 
>>>> On Mon, Jun 21, 2021 at 11:11 PM David Briggs  
>>>> wrote:
>>>> Hi Jiang Xu,
>>>> 
>>>> (Phenixbb added as I suspect this is Phenix not coot that has caused your 
>>>> issue)
>>>> 
>>>> Did you check the "add hydrogens" button in Phenix.refine? Sometimes this 
>>>> can erroneously add a second H to the ND of glycosylated Asn residues. (I 
>>>> assume this is because bond distances in the input PDB file fall outside 
>>>> Phenix's definitions of an Asn-NAG link).
>>>> 
>>>> If the second H is added, this breaks the refinement of the Asn-NAG bond.
>>>> 
>>>> My work around is to run "Ready Set" to add hydrogens as a separate job, 
>>>> and then manually inspect and correct the Asn residues as necessary before 
>>>> running Phenix.refine and _not_ checking the "add hydrogens" box.
>>>> 
>>>> I hope this fixes your problem.
>>>> 
>>>> Good luck,
>>>> 
>>>> Dave
>>>> 
>>>> --
>>>> Dr David C. Briggs
>>>> Senior Laboratory Research Scientist
>>>> Signalling and Structural Biology Lab
>>>> The Francis Crick Institute
>>>> London, UK
>>>> ==
>>>> about.me/david_briggs
>>>> 
>>>> From: CCP4 bulletin board  on behalf of Jiang Xu 
>>>> 
>>>> Sent: Tuesday, June 22, 2021 6:47:36 AM
>>>> To: CCP4BB@JISCMAIL.AC.UK 
>>>> Subject: [ccp4bb] missing covalent bond between asparagine and 
>>>> N-acetylglucosamine using coot carbohydrate module and phenix.refine
>>>>  
>>>>  
>>>> External Sender: Use caution.
>>>>  
>>>> Hello guys, 
>>>>I have

Re: [ccp4bb] missing covalent bond between asparagine and N-acetylglucosamine using coot carbohydrate module and phenix.refine

2021-06-21 Thread Paul Emsley

On 22/06/2021 06:47, Jiang Xu wrote:
    I have a problem building and refining an xtal structure. My protein has a N-glycosylation site and I 
want to add N-acetylglucosamine and manose to my protein structure. I used Coot's carbohydrate module and 
let Coot automatically build the sugar chain to the electron density. It worked pretty well, but I noticed 
that the bond between the amine group of asparagine and the C1 of N-acetylglucosamine is depicted as a 
dashed line, rather than a solid line in Coot.


Coot draws solid lines for bonds between neighbouring monomers in a polymer.
The bond between NAG and ASN is not such a bond - it is a link.
Links are drawn as dashed lines in Coot.

After refinement of the structure using Phenix.refine, I 
found the bond just disappeared, and the amine group still has two hydrogen atoms, which should contain one 
hydrogen atom.


If there is no link for a ASN, then there should be two hydrogen atoms add to 
the ND2.

I find it fascinating that these programs work so well together that it didn't 
even occur to you to examine
the conduit through which structral information is passed.

Paul.



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Re: [ccp4bb] missing covalent bond between asparagine and N-acetylglucosamine using coot carbohydrate module and phenix.refine

2021-06-21 Thread David Briggs
Hi Jiang Xu,

(Phenixbb added as I suspect this is Phenix not coot that has caused your issue)

Did you check the "add hydrogens" button in Phenix.refine? Sometimes this can 
erroneously add a second H to the ND of glycosylated Asn residues. (I assume 
this is because bond distances in the input PDB file fall outside Phenix's 
definitions of an Asn-NAG link).

If the second H is added, this breaks the refinement of the Asn-NAG bond.

My work around is to run "Ready Set" to add hydrogens as a separate job, and 
then manually inspect and correct the Asn residues as necessary before running 
Phenix.refine and _not_ checking the "add hydrogens" box.

I hope this fixes your problem.

Good luck,

Dave

--
Dr David C. Briggs
Senior Laboratory Research Scientist
Signalling and Structural Biology Lab
The Francis Crick Institute
London, UK
==
about.me/david_briggs


From: CCP4 bulletin board  on behalf of Jiang Xu 

Sent: Tuesday, June 22, 2021 6:47:36 AM
To: CCP4BB@JISCMAIL.AC.UK 
Subject: [ccp4bb] missing covalent bond between asparagine and 
N-acetylglucosamine using coot carbohydrate module and phenix.refine


External Sender: Use caution.

Hello guys,
   I have a problem building and refining an xtal structure. My protein has a 
N-glycosylation site and I want to add N-acetylglucosamine and manose to my 
protein structure. I used Coot's carbohydrate module and let Coot automatically 
build the sugar chain to the electron density. It worked pretty well, but I 
noticed that the bond between the amine group of asparagine and the C1 of 
N-acetylglucosamine is depicted as a dashed line, rather than a solid line in 
Coot. After refinement of the structure using Phenix.refine, I found the bond 
just disappeared, and the amine group still has two hydrogen atoms, which 
should contain one hydrogen atom.  So,  how to solve this problem?
[image.png]
Thank you,
Best,
Jiang Xu
Lin Chen's Research Group
University of Southern California



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[ccp4bb] missing covalent bond between asparagine and N-acetylglucosamine using coot carbohydrate module and phenix.refine

2021-06-21 Thread Jiang Xu
Hello guys,
   I have a problem building and refining an xtal structure. My protein has
a N-glycosylation site and I want to add N-acetylglucosamine and manose to
my protein structure. I used Coot's carbohydrate module and let Coot
automatically build the sugar chain to the electron density. It worked
pretty well, but I noticed that the bond between the amine group of
asparagine and the C1 of N-acetylglucosamine is depicted as a dashed line,
rather than a solid line in Coot. After refinement of the structure using
Phenix.refine, I found the bond just disappeared, and the amine group still
has two hydrogen atoms, which should contain one hydrogen atom.  So,  how
to solve this problem?
[image: image.png]
Thank you,
Best,
Jiang Xu
Lin Chen's Research Group
University of Southern California



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