Thursday, 1 March 2012

NCONT chain selection issue

From: Sampson, Jared
Date: 1 March 2012 20:08

Hello all -

Short version: NCONT from CCP4 v6.2.0 doesn't properly recognize comma-separated chain IDs with the source or target keyword.

I'm trying to use NCONT to determine contacts between antibody chains and their bound epitope as part of a programmatic workflow.  I'm using a Biopython Bio.Application.AbstractCommandline subclass to generate the command to be executed.  It ends up looking something like this:

ncont xyzin /path/to/xxxx.pdb <<eof
source L,H
target P
maxdist 4 
eof

The problem is, the output only identifies the contacts between chains L and P.  If I switch the order of the source to "H,L" it only identifies contacts between H and P.  Similarly, if I switch the source and target selections (i.e. "source P", "target L,H") I see the same behavior.  

I'm using NCONT from CCP4 v6.2.0 on Mac OS 10.7.3 installed via Fink.

A quick archives search produced a 2006 discussion about having the wrong ncont in the user's path, but mine appears to be correct:

$ which ncont
/sw/share/xtal/ccp4-6.2.0/bin/ncont

Any suggestions on what might be going on here?  I've pasted the full NCONT output below in case that might shed any light on the issue.  Of course, I could work around this by running each pair of chains separately, but I'd prefer to do it in one fell swoop.

Many thanks,

Jared

-


Here's the full output from NCONT with a test antibody-peptide complex from 1Q1J, first with "L,H" then with "H,L" as the source selections.

$ ncont xyzin 1Q1J.pdb <<eof
> source P
> target L,H
> maxdist 4 
> eof
 ###############################################################
 ###############################################################
 ###############################################################
 ### CCP4 6.2: NCONT                    version 6.2 :         ##
 ###############################################################
 User: jared  Run date:  1/ 3/2012 Run time: 14:22:07 


 Please reference: Collaborative Computational Project, Number 4. 1994.
 "The CCP4 Suite: Programs for Protein Crystallography". Acta Cryst. D50, 760-763.
 as well as any specific reference in the program write-up.


 ------------------------------------------------------------------------------

 PDB file 1Q1J.pdb has been read in.

 ------------------------------------------------------------------------------
  Input cards

 Data line--- source P
 Data line--- target L,H
 Data line--- maxdist 4 

 ------------------------------------------------------------------------------

 Selected  73  source atoms
 Selected  1611  target atoms

 ------------------------------------------------------------------------------

  23 contacts found:

      SOURCE ATOMS               TARGET ATOMS         DISTANCE

 /1/P/ 309(ILE). / CG2[ C]:  /1/L/  91(TRP). / CH2[ C]:   3.78
                             /1/L/  32(TYR). / CG [ C]:   3.93
                             /1/L/  32(TYR). / CD1[ C]:   3.47
                             /1/L/  32(TYR). / CE1[ C]:   3.86
 /1/P/ 312(GLY). / N  [ N]:  /1/L/  91(TRP). / CH2[ C]:   3.97
 /1/P/ 312(GLY). / CA [ C]:  /1/L/  91(TRP). / CH2[ C]:   4.00
 /1/P/ 313(PRO). / N  [ N]:  /1/L/  91(TRP). / CD2[ C]:   3.96
 /1/P/ 313(PRO). / CA [ C]:  /1/L/  91(TRP). / CD1[ C]:   3.94
 /1/P/ 313(PRO). / CB [ C]:  /1/L/  91(TRP). / CB [ C]:   3.82
                             /1/L/  95(ALA).B/ O  [ O]:   3.49
                             /1/L/  91(TRP). / CG [ C]:   3.93
 /1/P/ 313(PRO). / CG [ C]:  /1/L/  96(TRP). / NE1[ N]:   3.57
                             /1/L/  91(TRP). / CB [ C]:   3.95
                             /1/L/  96(TRP). / CD2[ C]:   3.73
                             /1/L/  96(TRP). / CE2[ C]:   3.27
                             /1/L/  96(TRP). / CZ2[ C]:   3.39
                             /1/L/  96(TRP). / CH2[ C]:   3.90
 /1/P/ 313(PRO). / CD [ C]:  /1/L/  91(TRP). / CE3[ C]:   3.91
                             /1/L/  96(TRP). / CE2[ C]:   3.95
                             /1/L/  96(TRP). / CZ2[ C]:   3.51
                             /1/L/  96(TRP). / CH2[ C]:   3.65
                             /1/L/  91(TRP). / CD2[ C]:   3.90
 /1/P/ 314(GLY). / N  [ N]:  /1/L/  95(ALA).B/ CB [ C]:   3.91


  Total 23 contacts

--------------------------------------------------------------------------

 NCONT:  Normal termination
Times: User:       0.0s System:    0.0s Elapsed:     0:00  
$ ncont xyzin 1Q1J.pdb <<eof
> source P
> target H,L
> maxdist 4 
> eof
 ###############################################################
 ###############################################################
 ###############################################################
 ### CCP4 6.2: NCONT                    version 6.2 :         ##
 ###############################################################
 User: jared  Run date:  1/ 3/2012 Run time: 14:22:26 


 Please reference: Collaborative Computational Project, Number 4. 1994.
 "The CCP4 Suite: Programs for Protein Crystallography". Acta Cryst. D50, 760-763.
 as well as any specific reference in the program write-up.


 ------------------------------------------------------------------------------

 PDB file 1Q1J.pdb has been read in.

 ------------------------------------------------------------------------------
  Input cards

 Data line--- source P
 Data line--- target H,L
 Data line--- maxdist 4 

 ------------------------------------------------------------------------------

 Selected  73  source atoms
 Selected  1756  target atoms

 ------------------------------------------------------------------------------

  98 contacts found:

      SOURCE ATOMS               TARGET ATOMS         DISTANCE

 /1/P/ 305(LYS). / O  [ O]:  /1/H/ 100(ASP).F/ N  [ N]:   3.95
                             /1/H/ 100(ASP).F/ CB [ C]:   3.59
 /1/P/ 305(LYS). / CB [ C]:  /1/H/ 100(GLU).E/ OE1[ O]:   3.70
                             /1/H/ 100(GLU).E/ OE2[ O]:   3.74
 /1/P/ 306(ARG). / N  [ N]:  /1/H/ 100(GLU).E/ OE1[ O]:   3.95
 /1/P/ 306(ARG). / CA [ C]:  /1/H/ 100(ASP).F/ O  [ O]:   3.46
 /1/P/ 306(ARG). / C  [ C]:  /1/H/ 100(ASP).F/ O  [ O]:   3.53
 /1/P/ 306(ARG). / CB [ C]:  /1/H/ 100(TYR).H/ CE1[ C]:   3.77
 /1/P/ 306(ARG). / CG [ C]:  /1/H/ 100(TYR).H/ CE1[ C]:   3.62
 /1/P/ 306(ARG). / CD [ C]:  /1/H/ 100(TYR).H/ CE1[ C]:   3.44
                             /1/H/ 100(TYR).H/ CZ [ C]:   3.69
                             /1/H/ 100(TYR).H/ OH [ O]:   3.45
 /1/P/ 306(ARG). / NE [ N]:  /1/H/ 100(TYR).H/ CZ [ C]:   3.97
                             /1/H/ 100(TYR).H/ OH [ O]:   3.21
 /1/P/ 306(ARG). / CZ [ C]:  /1/H/ 100(TYR).H/ OH [ O]:   3.30
 /1/P/ 306(ARG). / NH1[ N]:  /1/H/ 100(TYR).H/ OH [ O]:   3.54
 /1/P/ 306(ARG). / NH2[ N]:  /1/H/ 100(TYR).H/ OH [ O]:   3.88
 /1/P/ 307(ILE). / N  [ N]:  /1/H/ 100(ASP).F/ O  [ O]:   2.63
                             /1/H/ 100(ASP).F/ C  [ C]:   3.84
 /1/P/ 307(ILE). / CA [ C]:  /1/H/ 100(ASP).F/ O  [ O]:   3.51
 /1/P/ 307(ILE). / C  [ C]:  /1/H/ 100(TYR).H/ N  [ N]:   3.88
                             /1/H/ 100(ASP).F/ O  [ O]:   3.91
 /1/P/ 307(ILE). / O  [ O]:  /1/H/ 100(TYR).H/ CA [ C]:   3.53
                             /1/H/ 100(TYR).H/ O  [ O]:   3.78
                             /1/H/ 100(TYR).H/ CB [ C]:   3.41
                             /1/H/ 100(TYR).H/ CG [ C]:   3.85
                             /1/H/ 100(TYR).H/ CD1[ C]:   3.38
                             /1/H/ 100(TYR).G/ CA [ C]:   3.55
                             /1/H/ 100(TYR).G/ C  [ C]:   3.54
                             /1/H/ 100(TYR).H/ N  [ N]:   2.68
                             /1/H/ 100(ASP).F/ O  [ O]:   3.40
 /1/P/ 307(ILE). / CB [ C]:  /1/H/ 100(ASP).F/ O  [ O]:   3.57
 /1/P/ 307(ILE). / CG1[ C]:  /1/H/ 100(ASP).F/ O  [ O]:   3.88
                             /1/H/ 100(GLU).E/ OE1[ O]:   3.76
                             /1/H/ 100(GLU).E/ CB [ C]:   3.75
 /1/P/ 307(ILE). / CD1[ C]:  /1/H/ 100(GLU).E/ OE1[ O]:   3.42
 /1/P/ 308(HIS). / CA [ C]:  /1/H/ 100(TYR).H/ O  [ O]:   3.62
 /1/P/ 308(HIS). / C  [ C]:  /1/H/ 100(TYR).H/ O  [ O]:   3.55
 /1/P/ 308(HIS). / ND1[ N]:  /1/H/ 100(TYR).J/ CE1[ C]:   3.62
                             /1/H/ 100(TYR).J/ CZ [ C]:   3.79
                             /1/H/ 100(TYR).J/ OH [ O]:   3.03
                             /1/H/ 100(TYR).H/ CB [ C]:   3.78
                             /1/H/ 100(TYR).H/ CG [ C]:   3.96
 /1/P/ 308(HIS). / CE1[ C]:  /1/H/ 100(TYR).J/ OH [ O]:   3.50
 /1/P/ 309(ILE). / N  [ N]:  /1/H/ 100(TYR).H/ C  [ C]:   3.84
                             /1/H/ 100(TYR).H/ O  [ O]:   2.61
 /1/P/ 309(ILE). / CA [ C]:  /1/H/ 100(TYR).H/ O  [ O]:   3.44
 /1/P/ 309(ILE). / C  [ C]:  /1/H/ 100(TYR).H/ O  [ O]:   3.89
 /1/P/ 309(ILE). / O  [ O]:  /1/H/ 100(TYR).J/ CA [ C]:   3.97
                             /1/H/ 100(TYR).J/ CB [ C]:   3.96
                             /1/H/ 100(TYR).J/ CD1[ C]:   3.70
                             /1/H/ 100(TYR).H/ O  [ O]:   3.64
                             /1/H/ 100(TYR).I/ CA [ C]:   3.70
                             /1/H/ 100(TYR).I/ C  [ C]:   3.82
                             /1/H/ 100(TYR).J/ N  [ N]:   3.01
 /1/P/ 309(ILE). / CB [ C]:  /1/H/ 100(TYR).H/ O  [ O]:   3.44
 /1/P/ 309(ILE). / CG1[ C]:  /1/H/ 100(TYR).H/ O  [ O]:   3.63
 /1/P/ 313(PRO). / O  [ O]:  /1/H/  33(TRP). / CZ3[ C]:   3.17
                             /1/H/  33(TRP). / CH2[ C]:   3.95
 /1/P/ 313(PRO). / CB [ C]:  /1/H/  50(ARG). / NH1[ N]:   3.85
 /1/P/ 314(GLY). / C  [ C]:  /1/H/  33(TRP). / CH2[ C]:   3.80
 /1/P/ 314(GLY). / O  [ O]:  /1/H/  52(LYS). / NZ [ N]:   3.94
                             /1/H/  33(TRP). / CH2[ C]:   3.41
 /1/P/ 315(ARG). / CD [ C]:  /1/H/  33(TRP). / CZ3[ C]:   3.81
                             /1/H/  33(TRP). / CH2[ C]:   3.72
 /1/P/ 315(ARG). / NE [ N]:  /1/H/  33(TRP). / CE3[ C]:   3.72
                             /1/H/  33(TRP). / CZ3[ C]:   3.51
                             /1/H/ 100(TYR).J/ CG [ C]:   3.78
                             /1/H/ 100(TYR).J/ CD1[ C]:   3.88
                             /1/H/ 100(TYR).J/ CD2[ C]:   3.94
                             /1/H/  33(TRP). / CH2[ C]:   3.86
 /1/P/ 315(ARG). / CZ [ C]:  /1/H/  33(TRP). / CE3[ C]:   3.31
                             /1/H/  33(TRP). / CZ3[ C]:   3.53
                             /1/H/ 100(TYR).J/ CG [ C]:   3.93
                             /1/H/ 100(TYR).J/ CD2[ C]:   3.61
                             /1/H/ 100(TYR).J/ CE2[ C]:   3.72
                             /1/H/  33(TRP). / CD2[ C]:   3.44
                             /1/H/  33(TRP). / CE2[ C]:   3.78
                             /1/H/  33(TRP). / CH2[ C]:   3.87
 /1/P/ 315(ARG). / NH1[ N]:  /1/H/  33(TRP). / CG [ C]:   3.84
                             /1/H/  33(TRP). / CE3[ C]:   3.60
                             /1/H/  33(TRP). / CZ3[ C]:   3.77
                             /1/H/ 100(TYR).J/ CE2[ C]:   3.82
                             /1/H/  33(TRP). / CD2[ C]:   3.27
                             /1/H/  33(TRP). / NE1[ N]:   3.64
                             /1/H/  33(TRP). / CE2[ C]:   3.14
                             /1/H/  33(TRP). / CZ2[ C]:   3.38
                             /1/H/  33(TRP). / CH2[ C]:   3.67
 /1/P/ 315(ARG). / NH2[ N]:  /1/H/  33(TRP). / CB [ C]:   3.94
                             /1/H/  95(ASP). / CG [ C]:   3.66
                             /1/H/  95(ASP). / OD2[ O]:   3.28
                             /1/H/  95(ASP). / CB [ C]:   3.17
                             /1/H/  33(TRP). / CG [ C]:   3.77
                             /1/H/  33(TRP). / CE3[ C]:   3.38
                             /1/H/ 100(TYR).J/ CG [ C]:   3.88
                             /1/H/ 100(TYR).J/ CD2[ C]:   3.39
                             /1/H/ 100(TYR).J/ CE2[ C]:   3.82
                             /1/H/  33(TRP). / CD2[ C]:   3.49


  Total 98 contacts

--------------------------------------------------------------------------

 NCONT:  Normal termination
Times: User:       0.0s System:    0.0s Elapsed:     0:00  


----------
From: Eleanor Dodson

Thats why I love distang!

Eleanor
--



----------
From: Sampson, Jared
Thanks to Pius for the tip that I can use more than one "source" keyword.

ncont xyzin my.pdb <<eof
source L
source H
target P
eof

works like a charm!




--

On Mar 1, 2012, at 4:47 PM, Pius Padayatti wrote:

what if you add as follows

ncont xyzin /path/to/xxxx.pdb <<eof
source L,H
target P
maxdist 4
source H,L
target P
maxdist 4
eof

will it run? and give both?
just a thought




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