Sequence-based mutation analysis of ARSA

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Revision as of 19:51, 25 June 2011 by Kassner (talk | contribs)

Intro

We randomly picked 10 missense mutations from dbSNP and HGMD. The mutations are listed below, together with a pymol mutagenesis image and a description of the properties of the mutations.

mutation position reference mutation both
Asp-Asn 29
29 arsa asp.png
29 arsa asn.png
29 arsa both.png
Description of Asp-Asn
Aspartic acid (Asp)
Asparagine (Asn)

Aspartic acid is an acidic amino acid while Asparagine is a hydrophilic amino acid. So the mutation changes the behaviour towards water as well as the pH.

Pro - Ala 136
136 arsa PRO.png
136 arsa ALA.png
136 arsa both.png
Description of Pro-Ala
Proline (Pro)
Alanine (Ala)

Proline and Alanine are both hydrophobic amino acids. So the behaviour towards water does not change. As Proline is a cyclic amino acid, it can "break" alpha-helices and is structural very important. Alanine is one the the smallest amino acids and so the mutation from Pro to Ala should have a big influence on the structure of ARSA.

Gln-His 153
153 arsa GLN.png
153 arsa HIS.png
153 arsa both.png
Description of Gln-His
Glutamine (Gln)
Histidine (His)

Glutamine is a hydrophilic amino acid while Histidine is a basic amino acid. So the behaviour towards water changes as well as the charge of the amino acid. Also Gln and His are very different in structure, so His needs much more space than Gln, which should have a big influence on the structure of ARSA.

Trp-Cys 193
193 arsa TRP.png
193 arsa CYS.png
193 arsa both.png
Description of Trp-Cys
Tryptophan (Trp)
Cysteine (Cys)

Tryptophan is a hydrophobic, aromatic amino acid while Cysteine is a hydrophilic amino acid. So the behaviour towards water changes dramatically. Also, Trp is the largest amino acid while Cys is a rather small amino acid. So the space needed for the amino acid changes also. This should have a huge influence on the structure of ARSA.

Thr-Met 274
274 arsa THR.png
274 arsa MET.png
274 arsa both.png
Description of Thr-Met

Paste description of mutation here

Phe -Val 356
356 arsa PHE.png
356 arsa VAL.png
356 arsa both.png
Description of Phe-Val

Paste description of mutation here

Thr-Ile 409
409 arsa THR.png
409 arsa ILE.png
409 arsa both.png
Description of Thr-Ile

Paste description of mutation here

Asn-Ser 440
440 arsa ASN.png
440 arsa SER.png
440 arsa both.png
Description of Asn-Ser

Paste description of mutation here

Cys-Gly 489
489 arsa CYS.png
489 arsa GLY.png
489 arsa both.png
Description of Cys-Gly

Paste description of mutation here

Arg-His 496
496 arsa ARG.png
496 arsa HIS.png
496 arsa both.png
Description of Arg-His

Paste description of mutation here

SNAP

We ran snap using the following command:


snapfun -i ARSA.fasta -m mutants.txt -o snap.out

output:


nsSNP	Prediction	Reliability Index	Expected Accuracy
-----	------------	-------------------	-------------------
D29N	Non-neutral		7			96%
Q153H	 Neutral 		0			53%
T274M	Non-neutral		6			93%
T409I	Non-neutral		1			63%
C489G	Non-neutral		5			87%
W193C	Non-neutral		3			78%
F356V	 Neutral 		1			60%
N440S	Non-neutral		2			70%
R496H	 Neutral 		1			60%
P136A	Non-neutral		4			82%

In order to analyze all possible combinations of amino acid substitutions from the above mutated positions, we used the Generate Mutants tool on http://rostlab.org/services/snap/submit to create all possible exchanges from the following pattern: referenceAminoAcidPosition* . Then we again executed snap:


snapfun -i ARSA.fasta -m all_mutants.txt -o snap_all.out

Next, we wrote a perl script to parse and summarize the SNAP output in the following table, which shows which amino acid substitutions are Non-neutral or Neutral:

ref\mutation A R N D C Q E G H I L K M F P S T W Y V
D29 Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral
Q153 Non-neutral Non-neutral Neutral Non-neutral Non-neutral Non-neutral Non-neutral Neutral Non-neutral Non-neutral Non-neutral Neutral Non-neutral Neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral
T274 Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral
T409 Neutral Non-neutral Neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral
C489 Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral
W193 Non-neutral Non-neutral Neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral
F356 Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Neutral Non-neutral Non-neutral Neutral Neutral Neutral Non-neutral Neutral Non-neutral Non-neutral Non-neutral Non-neutral Neutral Neutral
N440 Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral
R496 Non-neutral Non-neutral Non-neutral Non-neutral Neutral Non-neutral Non-neutral Neutral Non-neutral Non-neutral Neutral Non-neutral Neutral Non-neutral Non-neutral Non-neutral Non-neutral Neutral Non-neutral
P136 Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral Non-neutral

Multiple sequence alignments

First, we downloaded the HSSP file for ARSA to get all proteins, which are homologuous to it. Then we downloaded all mammalian protein sequences from Uniprot. This was achieved by searching for the term taxonomy:40674, which codes for all mammalian protein sequences. We saved all sequences in one multiple fasta file. Then we extracted all homologuous mammalian proteins to human ARSA by mapping the ids from the HSSP file to sequence ids in the multi fasta file. This yielded 75 homologuous mammalian sequences to human ARSA.
Next, we calculated a multiple sequence alignments of these proteins (including ARSA) with Muscle. The Jalview image of the alignment is shown below.

Multiple sequence alignments of all 75 homologuous sequences using muscle

The following table shows the conservation of the original amino acid in the reference sequence and their mutations at the respective positions.

pos conservation - reference conservation - mutant
29 0.86 0
153 0.14 0
274 0.87 0
409 0.35 0.16
489 0.80 0.05
193 0.13 0
356 0.15 0
440 0.15 0
496 0.14 0.01
136 0.93 0

PSI-BLAST


blastpgp -i ARSA.fasta -d /data/blast/nr/nr -e 10E-6 -j 5 -Q psiblast.mat -o psiblast_eval10E_6.it.5.new.txt


Last position-specific scoring matrix computed, weighted observed percentages rounded down, information per position, and relative weight of gapless real matches to pseudocounts
          A  R  N  D  C  Q  E  G  H  I  L  K  M  F  P  S  T  W  Y  V   A   R   N   D   C   Q   E   G   H   I   L   K   M   F   P   S   T   W   Y   V
  29 D   -5 -5 -2  8 -7 -3 -1 -4 -4 -6 -7 -4 -6 -7 -5 -3 -4 -7 -6 -6    0   0   0 100   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0  2.49 1.56
 153 Q    3  2 -1  4 -4 -1 -1 -2  0 -2 -3 -3  4 -2 -3 -1 -2 -3 -2 -2   26  10   3  23   0   3   3   3   2   2   1   1  13   2   1   3   2   0   1   2  0.53 1.48
 274 T   -3 -4 -3 -4 -2 -4 -4 -5 -5 -4 -4 -4 -3 -5 -4  1  8 -6 -5 -3    0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   7  92   0   0   0  1.94 1.62
 409 T   -1  0  0 -1 -2 -1 -1  0 -1 -1 -1  0 -1 -1  3  0  1  6  0 -1    5   5   5   4   1   3   4   8   1   3   6   5   1   2  13   6   8  11   3   4  0.26 0.95
 489 C    2 -1  1 -4  8 -4 -4 -2 -1 -1 -2 -3 -1 -4 -4  0  0  5 -1 -3   15   4   8   0  36   0   0   2   1   3   3   1   1   0   0   6   5   9   2   0  0.99 1.22
 440 N   -5 -3  6  5 -6 -2 -1 -4 -3 -6 -6 -3 -6 -6  2 -2 -3 -6 -6 -5    0   1  46  36   0   1   2   0   0   0   0   1   0   0  10   1   1   0   0   0  1.48 1.67
 356 F   -3 -1 -5 -5 -3  0 -1 -6  1  3  0 -1  0  2 -6 -3 -2 -3  5  3    1   4   0   0   1   5   4   0   3  18   8   5   2   8   0   1   2   0  20  20  0.59 1.62
 193 W   -2  4  2  3 -5  0  0 -2  0 -3 -4  1 -3 -1 -2 -1 -2  1  1 -3    3  25  11  16   0   4   5   3   2   2   1   7   0   2   2   4   2   2   5   2  0.46 1.45
 136 P   -3 -5 -5 -5 -6 -4 -4 -5 -5 -6 -6 -4 -6 -7  9 -4 -4 -7 -6 -5    1   0   0   0   0   0   0   0   0   0   0   0   0   0  98   0   0   0   0   0  3.03 1.61
 496 R   -3  1  0 -3 -4  1  1 -1  1 -3  1  1 -2  2  4  0 -3 -1 -1 -3    1   7   4   1   0   5  10   4   3   1  16   9   0   9  20   8   1   1   1   1  0.34 0.96