I reproduced your minimization and I have hopefully the same pdb, which
correponds to the distorted N3 and N1 and dihedral omega angles of 148
and 150° respectively.
I believed these values were out of range even for cyclic peptide but if
you say that it is consistent with reality I have to trust you.
Many thanks again
arnuad
Le 29/04/2020 à 17:09, Junmei Wang a écrit :
> The N1 and N13 are almost planar (torsional angles of O=C-N-H are 177 and
> 179 degrees). I don't think they are like pyramidal nitrogen in amines. I
> think the slightly deviation from the ideal geometry is because your
> molecule is cyclic peptide.
>
> Best
>
> Junmei
>
>
> On Wed, Apr 29, 2020 at 10:52 AM Arnaud Bondon <
> arnaud.bondon.univ-rennes1.fr> wrote:
>
>> Hi,
>>
>> I looked at your min.pdb and for me the N13 displays a pyramidal
>> character and also the N1 a little
>>
>> May be less pronounced that my previous pdb but not really planar
>>
>> I start the same command, I'll tell you
>>
>> thanks
>>
>> arnaud
>>
>>
>>
>> Le 29/04/2020 à 16:12, Junmei Wang a écrit :
>>> I have tested your molecule using your prepin and frcmod files. I also
>> did
>>> igb=1 minimization for 10,000 steps. I did not observe weird behavior of
>>> amide groups. Please check if you can reproduce my result.
>>>
>>> All the best
>>>
>>> Junmei
>>>
>>> On Wed, Apr 29, 2020 at 4:44 AM Arnaud Bondon <
>> arnaud.bondon.univ-rennes1.fr>
>>> wrote:
>>>
>>>> Hi,
>>>>
>>>> Thanks for the two responses.
>>>>
>>>> About solvent I only used igb=1 when performing simulated annealing
>>>> under NMR restraints (sa.in)
>>>>
>>>> The prep directory is attached.
>>>>
>>>> Many thanks for your help
>>>>
>>>> sincerely
>>>>
>>>> arnaud
>>>>
>>>> Le 28/04/2020 à 23:02, Junmei Wang a écrit :
>>>>> Gaff adopted the good parameters from amber biomolecular force field.
>> So
>>>>> the peptide-like parameters should be similar. For you minimization,
>> did
>>>>> you consider solvent effect? If you send me your prep file, I will
>> check
>>>> if
>>>>> it is a force field issue or not.
>>>>>
>>>>> Best
>>>>>
>>>>> Junmei
>>>>>
>>>>> On Fri, Apr 24, 2020 at 11:02 AM David A Case <david.case.rutgers.edu>
>>>>> wrote:
>>>>>
>>>>>> On Fri, Apr 24, 2020, Arnaud Bondon wrote:
>>>>>>
>>>>>>> ). Clearly the N10 amide nitrogen
>>>>>>> has an pyramidal character. And the omega dihedral angles are not
>> good
>>>>>>> The molecule was prepared as a mol2 file Nitrogen are N.am
>>>>>> The input atoms types don't matter: you should look at the output
>> types
>>>>>> in the prep file. If this is a peptide-like molecule, it may be that
>>>>>> the gaff types don't do as well as the tuned Amber atom types.
>>>>>> You might want to see what happens if you request Amber atom types.
>>>>>>
>>>>>> I'm not sure whether GAFF has types that are specifically tuned for
>>>>>> peptide bonds or not...cc-ing Junmei here.
>>>>>>
>>>>>> ...good luck...dac
>>>>>>
>>>>>>
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>>>>> _______________________________________________
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>>>> --
>>>> POUR UNE RECONNAISSANCE DE LA PALESTINE DANS LES FRONTIERES DE 1967
>>>> OU UN ETAT COMMUN
>>>>
>>>> Arnaud BONDON
>>>> Equipe CORINT, UMR CNRS 6226
>>>> PRISM
>>>> CS 34317
>>>> Campus de villejean
>>>> Université de Rennes 1
>>>> 35043 RENNES Cedex France
>>>> tel: (0)2 23 23 65 61
>>>> arnaud.bondon.univ-rennes1.fr
>>>> http://iscr.univ-rennes1.fr
>>>>
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>>>>
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>>>> http://lists.ambermd.org/mailman/listinfo/amber
>> --
>> POUR UNE RECONNAISSANCE DE LA PALESTINE DANS LES FRONTIERES DE 1967
>> OU UN ETAT COMMUN
>>
>> Arnaud BONDON
>> Equipe CORINT, UMR CNRS 6226
>> PRISM
>> CS 34317
>> Campus de villejean
>> Université de Rennes 1
>> 35043 RENNES Cedex France
>> tel: (0)2 23 23 65 61
>> arnaud.bondon.univ-rennes1.fr
>> http://iscr.univ-rennes1.fr
>>
>> _______________________________________________
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>> http://lists.ambermd.org/mailman/listinfo/amber
>>
> _______________________________________________
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> http://lists.ambermd.org/mailman/listinfo/amber
--
POUR UNE RECONNAISSANCE DE LA PALESTINE DANS LES FRONTIERES DE 1967
OU UN ETAT COMMUN
Arnaud BONDON
Equipe CORINT, UMR CNRS 6226
PRISM
CS 34317
Campus de villejean
Université de Rennes 1
35043 RENNES Cedex France
tel: (0)2 23 23 65 61
arnaud.bondon.univ-rennes1.fr
http://iscr.univ-rennes1.fr
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Received on Wed Apr 29 2020 - 08:30:01 PDT
