[Chimera-users] access to pdb parser

[Eric Pettersen]

Hi JD,
	I have good news and I have bad news.  The good news it that using  
PDBio to do what you want is pretty easy.  The bad news is that you  
can't use it in a generic Python shell, only in Chimera's own Python  
shell.  This is because we use a modified version of Python so that  
the types we define in the C++ layer (Molecule, etc.) can have  
attributes added to them in the Python layer -- otherwise they would  
behave like the built-in Python types (dict, list. etc.) that can't  
have arbitrary attributes added to them.  We intend to improve our  
own code to make modifying Python unnecessary, but haven't gotten to  
it so far.
	Nonetheless, you can basically use Chimera in place of a Python  
interpreter.  "chimera --nogui script.py" will execute the Python  
script named script.py without bringing up the Chimera interface.   
Also, you can start Chimera normally and bring up the graphical  
interface to its interactive Python shell, IDLE (under Tools->General  
Controls) and type Python commands to that.
	Here's a session of me using PDBio in IDLE.  I've added some comments.

 >>> from chimera import PDBio  # import PDBio
 >>> pdbio = PDBio()  # create a PDBio instance
 >>> mols = pdbio.readPDBfile("/mol/pdb/gc/pdb1gcn.ent")  # read a  
PDB file given its file name
 >>> m = mols[0]  # readPDBfile() returned a list of models (NMR can  
have many) so get the model itself
 >>> m.pdbHeaders["HEADER"]  # each model will have a pdbHeaders  
dictionary, keyed by the record type, the values will be a list of  
strings -- the PDB records
['HEADER    HORMONE                                 17-OCT-77    
1GCN      1GCN   3']
 >>>

--Eric

On Jan 31, 2007, at 12:42 PM, Jean Didier Pie Marechal wrote:

> Hi Eric,
>
> Yes, that would be better to explain more what I'd like to do.
>
> I am planning to give a practical on computational (bio)chemistry  
> in my department next year. I'd stongly like to have the students  
> using chimera and python as their main tools (though both are tools  
> I am in process of learning :-)).
>
> One of the "simple things" I have in mind, is to obtain pdb infos  
> directly from the shell e.g list the SEQRES entry or access to the  
> resolution (REMARK 2), the crystallization conditions  etc. The  
> students will be chemists and I think that from a didactic point of  
> view, obtaining infos from the python shell would be better that  
> reading the pdb files, especially if we want to compare different  
> structures e.g. Writing a comand that gives you ALL the resolutions  
> of the 10 structures you loaded would be interesting. I looked at  
> the PDBio, but I can see how to catch REMARKS infos.
>
> I'd really like to have this work going on, but as you can see, I  
> am a bit lost in where to begin.
>
> Any help to tell me where to start would be fantastic!
>
> Cheers
>
> JD
>
>
>
>
> Dr. Jean-Didier Maréchal
> Professor Lector
> Unitat de Química Física
> Departament de Química
> Universitat Autònoma de Barcelona
> Edifici C.n.
> 08193 Cerdonyola (Barcelona)
> Tel: +34.935814988
> e-mail: JeanDidier.Marechal at uab.es
>
> ----- Missatge original -----
> De: Eric Pettersen <pett at cgl.ucsf.edu>
> Data: Dimarts, Gener 30, 2007 1:25 am
> Assumpte: Re: [Chimera-users] access to pdb parser
>
>> Hi JD,
>> 	Chimera does its PDB parsing in the C++ layer (the PDBio class in
>>
>> the Python layer).  There is a file named PDB.py in the mmCIF-
>> parsing
>> module, but it's not for parsing PDB files.  Perhaps if you
>> described
>> why you need Python PDB parsing I could suggest options -- using
>> PDBio possibly being one of them.
>>
>> --Eric
>>
>>                         Eric Pettersen
>>                         UCSF Computer Graphics Lab
>>                         pett at cgl.ucsf.edu
>>                         http://www.cgl.ucsf.edu
>>
>> On Jan 29, 2007, at 1:49 PM, Jean Didier Pie Marechal wrote:
>>
>>> Hello everyone,
>>>
>>> a short question. What is the right call for importing the
>>> pdbparser module in the chimera python shell? I found the PDB.py
>>
>>> module in the site-package mmlib, but I don't know how to import
>> it...>
>>> Thanks a lot,
>>>
>>> JD
>>>
>>>
>>> Dr. Jean-Didier Maréchal
>>> Professor Lector
>>> Unitat de Química Física
>>> Departament de Química
>>> Universitat Autònoma de Barcelona
>>> Edifici C.n.
>>> 08193 Cerdonyola (Barcelona)
>>> Tel: +34.935814988
>>> e-mail: JeanDidier.Marechal at uab.es
>>>
>>>
>>> _______________________________________________
>>> Chimera-users mailing list
>>> Chimera-users at cgl.ucsf.edu
>>> http://www.cgl.ucsf.edu/mailman/listinfo/chimera-users
>>
>>
>
>