Difference between revisions of "Lab Journal - Task 6 (PAH)"

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(Calculate and analyze correlated mutations)
(Multiple Sequence Alignment)
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The multiple alignments are downloaded from the PFAM server and are converted into a freecontact readable format using a2m2aln.
 
The multiple alignments are downloaded from the PFAM server and are converted into a freecontact readable format using a2m2aln.
 
#Protein H-RAS: <br> <code>/usr/share/freecontact/a2m2aln -q '^RASH_HUMAN/(\d+)' --quiet < PF00071_full.txt > PF00071.aln </code>
 
#Protein H-RAS: <br> <code>/usr/share/freecontact/a2m2aln -q '^RASH_HUMAN/(\d+)' --quiet < PF00071_full.txt > PF00071.aln </code>
#For our protein PAH, we have two domains. As the Biopterin-domain is said to be causing PKU if damaged, we used the PFAM alignment of this domain:<br><code> /usr/share/freecontact/a2m2aln -q '^PH4H_HUMAN/(\d+)' --quiet < PF00351_full.txt > PF00351.aln</code>
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#For our protein PAH, we have two domains. We used the PFAM alignment of the biopterin domain:<br><code> /usr/share/freecontact/a2m2aln -q '^PH4H_HUMAN/(\d+)' --quiet < PF00351_full.txt > PF00351.aln</code>
   
 
== Calculate and analyze correlated mutations ==
 
== Calculate and analyze correlated mutations ==

Revision as of 11:59, 23 June 2013

Multiple Sequence Alignment

The multiple alignments are downloaded from the PFAM server and are converted into a freecontact readable format using a2m2aln.

  1. Protein H-RAS:
    /usr/share/freecontact/a2m2aln -q '^RASH_HUMAN/(\d+)' --quiet < PF00071_full.txt > PF00071.aln
  2. For our protein PAH, we have two domains. We used the PFAM alignment of the biopterin domain:
    /usr/share/freecontact/a2m2aln -q '^PH4H_HUMAN/(\d+)' --quiet < PF00351_full.txt > PF00351.aln

Calculate and analyze correlated mutations

  1. Freecontact is used to calculate CN-score for the multiple alignments:
    freecontact -o evfold < '<PFAM-ID>.aln' > <PFAM-ID>.evfold
  2. contact_map.pl extracts all residue pairs with less than 5 Ångstrom minimum atom distance:
    perl contact_map.pl -pdb <pdb-file> -out <output-file>
  3. extract_pairs.pl extracts all residue pairs with distance >5, if such a pair also is included in the output of contact_map.pl it is marked with 'TP' (true positive) else with 'FP' (false positive):
    perl extract_pairs.pl -inp <PFAM-ID>.evfold -map <contact_map.pl output-file> -out <output-file>
  4. the results are sorted (CN-score descending) for both all and extracted residue pairs:
    sort -k 6 -g -r <PFAM-ID>.evfold >sort_<PFAM-ID>.txt
  5. CN_dist2.R makes histograms for the CN-Score distribution (for all and extracted pairs). Furthermore it calculates the top L-Score (L = protein length) for each residue i that belongs to the top L:
    top L-Score(i) = (sum of CN scores for residue i)/mean(CN-Scores of top L)
  6. contact_map.R creates a contact map with the output-files of the two perl scripts above (pdb = reference structure, extracted = predicted).
  7. Evcouplings
    Reference structure for Ras is 121p.
    For the biopterin family we have to set the starting position to 106 to get a multiple alignment.

The perl and R scripts can be found in /mnt/home/student/waldraffs/masterpractical/Task6.

Calculate structural model

The length of Pfam alignment of H-Ras is 160, therefore we take following number of contacts: 64, 104, 160.
For biopterin the protein length is 346 as we only make an alignment with amino acids 106 to 452. So we take 138, 225 and 346 as number of contacts.