Dear Krisztina,
The specificity of your disaccharide is only the 'protective' group(s)
(sugar chemistry) on 'some' sugar hydroxyl group(s).
You could follow the approach described below to compute charges for
this protective group (an others) separatly from the sugar units...
http://q4md-forcefieldtools.org/REDDB/projects/F-85/
regards, Francois
> Thanks for the reply! As Francois suggested, charges I should be
> able to get from the RED server. For using the GLYCAM parameters I
> need to use the GLYCAM residues and atom types. For the first
> bGlcpNAc I used 1YB-1, then I made muramic acid as GlcpNAc with 3
> connections: on position 4 the first NAG is connected, position 1
> terminated with an OH and on position 3 lactic acid is attached. So
> I used WYB-2, ROH-3 and a LAC-4, but the bonds are not generated
> correctly between them in leap after loading the pdb file. I am just
> only learning how leap works and here I need a branch and I do not
> know how to make it. Do I have to manually edit the bonds in leap?
> Are the residue types I used correct?
>
> I tried the GLYCAM oligosaccharide builder, understandably there was
> no lactic acid, but also I did not find a way to make a branch on
> position 3 as there were only linkages from position 1 or 2.
> --- On Sun, 12/16/12, Lachele Foley (Lists) <lf.list.gmail.com> wrote:
>
> From: Lachele Foley (Lists) <lf.list.gmail.com>
> Subject: Re: [AMBER] branched disaccharide in leap
> To: "AMBER Mailing List" <amber.ambermd.org>
> Date: Sunday, December 16, 2012, 4:01 AM
>
> We don't have structural and charge information for muramic acid. I'm
> not aware that anyone in the group is working on it either. Our
> parameters should work, but you would need to develop charges.
>
>
> On Sat, Dec 15, 2012 at 5:16 PM, Aron Broom <broomsday.gmail.com> wrote:
>> Have you considered using the Glycan builder by the group that makes the
>> AMBER Glycam forcefield (Woods group)?
>>
>> You can find their main website here http://glycam.ccrc.uga.edu/ccrc/
>>
>> Follow the amber utilities or somesuch and then carbohydrate builder or
>> something. This will allow you to not only generate a PDB easily, but all
>> the residues will have the appropriate names.
>>
>> ~Aron
>>
>> On Sat, Dec 15, 2012 at 3:25 PM, Krisztina Feher
>> <feher_krisztina.yahoo.com>wrote:
>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> Dear All,
>>>
>>>
>>>
>>>
>>>
>>> I am trying to generate a disaccharide consisting
>>> bGlcpNAc[1,4]aGlcpNAc[3-]-lactic acid in leap, see in the attched pdb file.
>>> Could someone suggest me the monosaccharide units I should use for
>>> this molecule? My own attempt from 4 residues ROH 1, WYB 2, 1YB 3 and
>>> a self-constructed LAC 4 residue has incorrect connections, please, see
>>> the screenshot of molecule in the editor.
>>>
>>> GlcpNAc[3-]-lactic acid is in fact muramic
>>> acid, but I did not see separate PDB code for in the GLYCMA06.prep
>>> file, so I made it from GlcpNAc and a lib file for lactic acid in
>>> antechamber with gaff atomtypes. Is there a better way for muramic acid?
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Received on Tue Dec 18 2012 - 23:00:04 PST
