Dear Martin
I have attempted to use Mars for automatic assignment in the past but
to no real avail. To address you first point about setting up CB-1
and CA-1 resonances, this I tend to do manually when I pick and assign
roots. Simply select the i-1 peaks in whichever spectrum you are
using, ensure that the 1H and 15N dimensions have the same spin system
as the i residue, but for the 13C dimension you need just select new
and you get some number in square brackets. From here select the
peak/peaks for the i-1 and using the right mouse button, select
assign, set sequential spin systems and then the appropriate option
for your spectrum, i.e. if 13C is in F3, select F1 0, F2 0, F3 -1. If
you do this for all residues, you will get a shift list with CA-1 etc
in it.
Regarding, psipred and the number of amino acids Mars wants, in
Analysis 2.1.5, which I use in Ubuntu, this error does not appear. I
simply don't get any sequential connectivities after three iterations,
so again Mars doesn't work for me either.
Hope this helps so you can tell me how to get it working.
Kind Regards
Simon Skinner
Quoting Martin Ballaschk <[log in to unmask]>:
> So no answer means:
>
> a) no one uses MARS
> b) that was way to much text in that help request
> c) everybody who knows decided not to answer because overlong
> requests need to be punished ;)
>
> So, I'd still be delighted if anyone could share her experience.
>
> Regards
> Martin Ballaschk
>
> On 02.12.2011, at 14:47, Martin Ballaschk wrote:
>
>> Hi there.
>>
>> Using the MARS wrapper of CCPN Analysis 2.2 remains so far an
>> unsolved challenge to me.
>>
>> Problem Nr. 1:
>>
>> CB and CA resonances need to be typed before fed into MARS, and
>> MARS obviously needs to know if the resonance belongs to the
>> current (C, CB, CA) or the preceding (C-1, CB-1, CA-1 etc.)
>> residue. I don't see a way to assign that within CCPN. All I can do
>> is typing the resonance inside the assignemnt popup, by making a
>> new carbon resonance, setting it to the "Same Spin System" and give
>> the type C, CA, CB, etc.
>>
>> Also from a fully assigned protein, where the sequential
>> information is definitely there, the preceding residue shifts seems
>> *not* to be easily exported from CCPN into MARS. The corresponding
>> "-1" columns are empty in the exported CS tables, which can be
>> found in the "mars" directory inside the project directory.
>>
>> What am I doing wrong here?
>>
>> Problem Nr. 2
>>
>> For some reason, CCPN demands a local install of Psipred to
>> generate the secondary structure information which also can be
>> obtained via the Psipred web service. CCPN also demands the .ss and
>> .ss2 files that a local installation of Psipred is generating, but
>> MARS does not use anyway. (It just needs the regular ".horiz" file.)
>>
>> %%%
>>
>> I've run in to several other problems, e.g. will blastpgp – which
>> is used by standard Psipred fail silently, but the experimental
>> Psipredplus using BLAST+ works fine. Also, my Mac and its tcsh has
>> some problems with the standard Psipred scripts.
>>
>> Another problem is that the Mac OS MARS binary provided by Markus
>> Zweckstetter is compiled with support for PowerPC processors, which
>> are not built into any Apple computers for more than five years
>> now, IIRC. In the last version of the Mac Operating System, PPC
>> support was dropped and will not return.
>>
>> Below you will find a list of what I've tried so far.
>>
>> I hope someone can help me with this. How are you doing it?
>>
>> All the best
>> Martin Ballaschk
>>
>>
>>
>>
>> %%%
>>
>> Howto (not) use MARS automated protein sequence assignment with
>> CCPN Analysis
>> =============================================================================
>>
>>
>> 1.) Setup Psipred and BLAST+
>>
>> Download and install NCBI/BLAST+ binaries
>> ftp://ftp.ncbi.nlm.nih.gov/blast/executables/LATEST/
>>
>> 2.) Setup experimental version PSIPRED running with BLAST+
>>
>> Download PSIPRED from here:
>> http://bioinf.cs.ucl.ac.uk/software_downloads/
>>
>> Make & Install PSIPRED according to Readme
>>
>> Download uniref90 in FASTA format (4 GB)
>>
>> prepare uniref database according to README:
>>
>> $ pfilt uniref90.fasta > uniref90filt
>> $ formatdb -t uniref90filt -i uniref90filt
>>
>> Set all the paths in the psipredplus script and run it on your
>> protein sequence (FASTA format):
>>
>> $ ./pipredplus myprotein.fasta
>>
>> The resulting files are ...
>>
>> myprotein.horiz
>> myprotein.ss
>> myprotein.ss2
>>
>> ... which can be placed inside the psipred directory of the CCPN
>> project, in case the Psipred wrapper of CCPN does not work.
>>
>> set the following variable in ~/.cshrc
>> setenv PSIPRED_DIR /path/to/psipred_dir
>>
>> 3.) Setup MARS
>>
>> Get the MARS binary (Mac PPC, Linux) from Markus Zweckstetter's
>> Website (MPI BPC)
>> http://www.mpibpc.mpg.de/groups/zweckstetter/_links/software_mars.htm
>>
>> set PATH variables in ~/.cshrc
>> setenv MARSHOME /path/to/mars/bin
>> alias runmars $MARSHOME/runmars
>>
>> Try a expample data set from examples directory to check if all
>> paths are set correctly.
>>
>>
>> 5.) Get CCPN 2.2 (today a buggy "leading edge release")
>>
>> Assignment > Automated Seq. Assignment > Automation
>>
>> If all environment variables are set right, you should have the
>> choice between Nexus (built-in) and MARS. Set all the parameters
>> according to your spectra and protein properties.
>>
>> 6.) Hit "Run Mars"
>>
>> CCPN will ask Psipred to make all three secondary structure files
>> generated by the local Psipred; however if you place them into the
>> "psipred" directory inside the project directory, it will accept
>> them.
>> This is done by a little script sitting in
>> CCPNPATH/ccpnmr2.2/ccpnmr2.2/python/ccpnmr/analysis/wrappers/Psipred.py
>>
>> Next step is CCPN exporting a MARS compatible chemical shift list.
>> This is done by the built-in export module.
>>
>> Next is MARS run by a script
>> CCPNPATH/ccpnmr2.2/ccpnmr2.2/python/ccpnmr/analysis/wrappers/Mars.py
>>
>> 7.) Watch the program fail.
>>
>> The number of chemical shifts has to be identical to the number of
>> amino acids in my protein - what about peaks disappearing due to
>> conformational or proton exchange?
>
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