Print

Print


One thing to beware of is that of course un-released structures may have
the code that you choose - structures can be on hold for over a year (the
rules say a year but in practice release is often slower) and any new
ligands and codes with them. Ligand codes are assigned at deposition and
the description stored privately in a wwPDB database I believe. So your
ligand code may be already there but not visible until it is copied into
the public Chemical Component Dictionary at the time of release.

Conversely your 'new' ligand _structure_ may be in an un-released entry
deposited by some other crystallographer and already assigned a 3-letter
code. So your choice will be overwritten at deposition in any case.

This produces a problem when multiple competing groups deposit structures
containing the same novel ligand. As the database will not expect
duplicates, only the first depositor will get assigned a new 3-letter code.

However then there should be alarm bells for the second depositor if their
'novel' ligand turns out to have a pre-existing three letter code! I
suspect there must have been cases where this happened but was not spotted
by the depositors. But if it happens to you then maybe it's time to speed
up publication...

I don't know if it has happened that one crystallographer has 'hastened'
the release of the ligand description of another worker by publishing it in
complex with a solved macromolecule. Perhaps the clever people at the PDB
do a switch at the last minute?

Best wishes,
 Martyn

Martyn Symmons
Cambridge






On Mon, Jun 8, 2015 at 3:12 AM, Lau Sze Yi (SIgN) <
[log in to unmask]> wrote:

> Thanks Eleanor for relaying my question from COOT and everyone that
> follows up with the thread.
>
> So this new ligand code search feature will be available in Phenix Gui?
> Look forward to it.
>
> Thanks,
> Sze Yi
>
>
>
>
> From: Nigel Moriarty <[log in to unmask]>
> Reply-To: Nigel Moriarty <[log in to unmask]>
> Date: Sunday, 7 June 2015 11:18 pm
> To: "[log in to unmask]" <[log in to unmask]>
> Subject: Re: [ccp4bb] New ligand 3-letter code
>
> Ed
>
> Thanks for the feature request. I will be available in the next nightly
> build.
>
> nigel% elbow.get_new_ligand_code "A?3"
>
> Unique ligand code : AV3
>
> Cheers
>
> Nigel
>
> ---
> Nigel W. Moriarty
> Building 64R0246B, Physical Biosciences Division
> Lawrence Berkeley National Laboratory
> Berkeley, CA 94720-8235
> Phone : 510-486-5709     Email : [log in to unmask]
> Fax   : 510-486-5909       Web  : CCI.LBL.gov
>
> On Sat, Jun 6, 2015 at 4:20 PM, Edward A. Berry <[log in to unmask]>
> wrote:
>
>> Neat! It's true the PDB will choose a unique code for you,
>> but they will use what you supply if it is already unique,
>> and it is nice to be able to choose something that can help
>> you remember what it stands for.
>> Gone are the days when we could choose meaningfull pdb ID's
>> (like 1PRC, 2PRC, 3PRC etc are all photosynthetic reaction center),
>> but there is still some freedom in choosing the ligand ID's.
>> They are filling up fast, though!
>>
>> locust 123% elbow.get_new_ligand_code AC
>> Unique ligand code : AC3
>>
>> locust 129% elbow.get_new_ligand_code "A?3"
>> Unique ligand code : A?3
>>
>> eab
>>
>> On 06/06/2015 12:13 PM, Nigel Moriarty wrote:
>>
>>> I wrote something a while ago the finds an unused code.
>>>
>>> % elbow.get_new_ligand_code
>>>>
>>>
>>> Unique ligand code : 7V8
>>>
>>> % elbow.get_new_ligand_code A
>>>>
>>>
>>> Unique ligand code : A6E
>>>
>>>
>>> Cheers
>>>
>>> Nigel
>>>
>>> ---
>>> Nigel W. Moriarty
>>> Building 64R0246B, Physical Biosciences Division
>>> Lawrence Berkeley National Laboratory
>>> Berkeley, CA 94720-8235
>>> Phone : 510-486-5709     Email : [log in to unmask]
>>> Fax   : 510-486-5909       Web  : CCI.LBL.gov <http://CCI.LBL.gov>
>>>
>>> On Fri, Jun 5, 2015 at 6:59 AM, Eleanor Dodson <
>>> [log in to unmask] <mailto:[log in to unmask]>> wrote:
>>>
>>>
>>>     I use any 3 letter/number code that i want. If you read the
>>> corresponding cif file into coot it is used in preference to any in the
>>> library. The PDB deposition team will assign a code if it is a new ligand
>>> to the database. Could you relay this to original poster?
>>>
>>>     Thanks
>>>
>>>     Jim Brannigan
>>>
>>>
>>>     On 5 June 2015 at 14:58, Eleanor Dodson <[log in to unmask]
>>> <mailto:[log in to unmask]>> wrote:
>>>
>>>         OK - thank you.
>>>         How are things?
>>>         E
>>>
>>>
>>>         ---------- Forwarded message ----------
>>>         From: *Jim Brannigan* <[log in to unmask] <mailto:
>>> [log in to unmask]>>
>>>         Date: 5 June 2015 at 14:39
>>>         Subject: Re: New ligand 3-letter code
>>>         To: Eleanor Dodson <[log in to unmask] <mailto:
>>> [log in to unmask]>>
>>>
>>>
>>>         Hi Eleanor
>>>
>>>         I use any 3 letter/number code that i want. If you read the
>>> corresponding cif file into coot it is used in preference to any in the
>>> library. The PDB deposition team will assign a code if it is a new ligand
>>> to the database. Could you relay this to original poster?
>>>
>>>         Thanks
>>>
>>>         Jim Brannigan
>>>
>>>         On 5 June 2015 at 11:28, Eleanor Dodson <
>>> [log in to unmask] <mailto:[log in to unmask]>> wrote:
>>>
>>>             I use your method - trial & error..
>>>             It would be nice if at least there was a list somewhere of
>>> unassigned codes!
>>>
>>>
>>>             On 5 June 2015 at 09:16, Lau Sze Yi (SIgN) <
>>> [log in to unmask] <mailto:
>>> [log in to unmask]>> wrote:
>>>
>>>                 Hi,
>>>
>>>                 What is the proper way of generating 3-letter code for a
>>> new ligand? As of now, I insert my ligand in Coot using smiles string and
>>> for the 3-letter code I picked a non-existent code by trial and error (not
>>> very efficient). A cif file with corresponding name which I generated using
>>> Phenix was imported into Coot.
>>>
>>>                 I am sure there is a proper way of doing this.
>>> Appreciate your feedback.
>>>
>>>                 Regards,
>>>                 Sze Yi
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>