Difference between revisions of "Sequence-based analyses of ARS A"

From Bioinformatikpedia
(GOPET)
Line 591: Line 591:
 
| '''A4'''
 
| '''A4'''
 
|[[File:leuko_A4_phobius.png|200px]]
 
|[[File:leuko_A4_phobius.png|200px]]
  +
| FT SIGNAL 1 17 <br>
|
 
  +
FT REGION 1 1 N-REGION.<br>
  +
FT REGION 2 12 H-REGION.<br>
  +
FT REGION 13 17 C-REGION.<br>
  +
FT TOPO_DOM 18 700 NON CYTOPLASMIC.<br>
  +
FT TRANSMEM 701 723 <br>
  +
FT TOPO_DOM 724 770 CYTOPLASMIC.<br>
  +
 
|[[File:leuka_A4_polyphobius.png|200px]]
 
|[[File:leuka_A4_polyphobius.png|200px]]
 
| FT SIGNAL 1 17 <br/>
 
| FT SIGNAL 1 17 <br/>
Line 603: Line 610:
 
| ''' ARS A '''
 
| ''' ARS A '''
 
|[[File:leuko_arsa_phobius.png|200px]]
 
|[[File:leuko_arsa_phobius.png|200px]]
  +
|FT SIGNAL 1 28 <br>
|
 
  +
FT REGION 1 6 N-REGION.<br>
  +
FT REGION 7 18 H-REGION.<br>
  +
FT REGION 19 28 C-REGION.<br>
  +
FT TOPO_DOM 29 507 NON CYTOPLASMIC.<br>
  +
 
|[[File:leuka_arsa_polyphobius.png|200px]]
 
|[[File:leuka_arsa_polyphobius.png|200px]]
 
| FT SIGNAL 1 16 <br/>
 
| FT SIGNAL 1 16 <br/>
Line 613: Line 625:
 
| ''' BACR '''
 
| ''' BACR '''
 
|[[File:leuko_bacr_phobius.png|200px]]
 
|[[File:leuko_bacr_phobius.png|200px]]
  +
| FT TOPO_DOM 1 22 NON CYTOPLASMIC. <br>
|
 
  +
FT TRANSMEM 23 42 <br>
  +
FT TOPO_DOM 43 53 CYTOPLASMIC.<br>
  +
FT TRANSMEM 54 76 <br>
  +
FT TOPO_DOM 77 95 NON CYTOPLASMIC.<br>
  +
FT TRANSMEM 96 114 <br>
  +
FT TOPO_DOM 115 120 CYTOPLASMIC.<br>
  +
FT TRANSMEM 121 142 <br>
  +
FT TOPO_DOM 143 147 NON CYTOPLASMIC.<br>
  +
FT TRANSMEM 148 169 <br>
  +
FT TOPO_DOM 170 189 CYTOPLASMIC.<br>
  +
FT TRANSMEM 190 212 <br>
  +
FT TOPO_DOM 213 217 NON CYTOPLASMIC.<br>
  +
FT TRANSMEM 218 237 <br>
  +
FT TOPO_DOM 238 262 CYTOPLASMIC.<br>
 
|[[File:leuko_bacr_polyphobius.png|200px]]
 
|[[File:leuko_bacr_polyphobius.png|200px]]
 
| FT TOPO_DOM 1 21 NON CYTOPLASMIC. <br/>
 
| FT TOPO_DOM 1 21 NON CYTOPLASMIC. <br/>
Line 633: Line 659:
 
| ''' INSL5 '''
 
| ''' INSL5 '''
 
|[[File:leuko_insl5_phobius.png|200px]]
 
|[[File:leuko_insl5_phobius.png|200px]]
  +
|FT SIGNAL 1 22 <br>
|
 
  +
FT REGION 1 5 N-REGION.<br>
  +
FT REGION 6 17 H-REGION.<br>
  +
FT REGION 18 22 C-REGION.<br>
  +
FT TOPO_DOM 23 135 NON CYTOPLASMIC.<br>
 
|[[File:leuko_insl5_polyphobius.png|200px]]
 
|[[File:leuko_insl5_polyphobius.png|200px]]
 
| FT SIGNAL 1 22 <br/>
 
| FT SIGNAL 1 22 <br/>
Line 643: Line 673:
 
| '''LAMP1 '''
 
| '''LAMP1 '''
 
|[[File:leuko_lamp1_phobius.png|200px]]
 
|[[File:leuko_lamp1_phobius.png|200px]]
  +
|FT SIGNAL 1 28 <br>
|
 
  +
FT REGION 1 10 N-REGION.<br>
  +
FT REGION 11 22 H-REGION.<br>
  +
FT REGION 23 28 C-REGION.<br>
  +
FT TOPO_DOM 29 381 NON CYTOPLASMIC.<br>
  +
FT TRANSMEM 382 405 <br>
  +
FT TOPO_DOM 406 417 CYTOPLASMIC.<br>
 
|[[File:leuko_lamp1_polyphobius.png|200px]]
 
|[[File:leuko_lamp1_polyphobius.png|200px]]
 
| FT SIGNAL 1 28 <br/>
 
| FT SIGNAL 1 28 <br/>
Line 655: Line 691:
 
| ''' RET4 '''
 
| ''' RET4 '''
 
|[[File:leuko_ret4_phobius.png|200px]]
 
|[[File:leuko_ret4_phobius.png|200px]]
  +
|FT SIGNAL 1 18 <br>
|
 
  +
FT REGION 1 2 N-REGION.<br>
  +
FT REGION 3 13 H-REGION.<br>
  +
FT REGION 14 18 C-REGION.<br>
  +
FT TOPO_DOM 19 201 NON CYTOPLASMIC.<br>
 
|[[File:leuko_ret4_polyphobius.png|200px]]
 
|[[File:leuko_ret4_polyphobius.png|200px]]
 
| FT SIGNAL 1 18 <br/>
 
| FT SIGNAL 1 18 <br/>

Revision as of 15:35, 3 June 2011

Additional Proteins

The following proteins are additionally used for the prediction of transmembrand alpha-helices and signal peptides and for the prediction of GO Terms:

BACR

BACR_HALSA is a bacterial membrane protein...

type Position ' Description
Topological domain 14 – 23 Extracellular
Transmembrane 24 – 42 Helical; Name=Helix A
Topological domain 43 – 56 Cytoplasmic
Transmembrane 57 – 75 Helical; Name=Helix B
Topological domain 76 – 91 Extracellular
Transmembrane 92 – 109 Helical; Name=Helix C
Topological domain 110 – 120 Cytoplasmic
Transmembrane 121 – 140 Helical; Name=Helix D
Topological domain 141 – 147 Extracellular
Transmembrane 148 – 167 Helical; Name=Helix E
Topological domain 168 – 185 Cytoplasmic
Transmembrane 186 – 204 Helical; Name=Helix F
Topological domain 205 – 216 Extracellular
Transmembrane 217 – 236 Helical; Name=Helix G
Topological domain 237 – 262 Cytoplasmic


RET 4

  • RET4_HUMAN is a human retinal-binding protein. It delivers retinol from the liver stores to the peripheral tissues. Defects can cause night vision problems.

no regions available


INSL 5

  • INSL5_HUMAN is a human insulin-like peptide. It consists of two chains and may have a role in gut contractility or in thymic development and regulation.

no regions available


LAMP 1

  • LAMP1_HUMAN is a human membrane glycoprotein. It presents cabohydrate ligands to selectins.
type Position ' Description
Topological Domain 29 - 382 Lumenal
Transmembrane 383 - 405 Helical
Topological Domain 406 - 417 Cytoplasmic
Region 29 - 194 First lumenal domain
Region 195 - 227 Hinge
Region 228 - 382 Second lumenal domain


A 4

  • A4_HUMAN is a human cell surface receptor involved in neurite growth, neuronal adhesion and axonogenesis. It can be involved in Alzheimer disease and Amyloidosis.
type Position ' Description
Topological domain 18 - 699 Extracellular
Transmembrane 700 - 723 Helical
Topological domain 724 - 770 Cytoplasmic
Domain 291 - 341 BPTI / Kunitz inhibitor
Region 96 - 110 Heparin-binding
Region 181 - 188 Zinc-binding
Region 391 - 423 Heparin-binding
Region 491 - 522 Heparin-binding
Region 523 - 540 Collagen-binding
Region 732 - 751 Interaction with G(o)-alpha
Motif 724 - 734 Basolateral sorting signal
Motif 759 - 762 NPXY motif; contains endocytosis signal
Compositional bias 230 - 260 Asp/Glu-rich (acidic)
Compositional bias 274 - 280 Poly-Thr

Secondary Structure Prediction

PSI-PRED

PSI-PRED creates a profile obtained from a PSI-BLAST search, which is fed into a feed-forward neural network. The output of this network then serves as input of a second network, which yields the final prediction. The average Q3 score, reached by PSI-PRED is 80,3 %. <ref name="psipred">Jones, D. T.. "[Protein secondary structure prediction based on position-specific scoring matrices.]". J Mol Biol, 1999</ref>

Jpred

Jpred also uses a neural network to predict secondary structure. The prediction relies on the Jnet algorithm, wich either takes a multiple sequence alignment or a single sequence as input. If a single sequence is passed to the program, Jpred also uses sequence profiles derived from a PSI-BLAST search. It reaches an average Q3 score up to 81,5 %. <ref name="jpred">Cole, C. and Barber, J. D. and Barton, G. J.. "[The Jpred 3 secondary structure prediction server.]". Nucleic Acid Res, 2008</ref>

DSSP

DSSP is a database of protein secondary structure assignments for all proteins in PDB. It is based on a method, which takes the 3D coordinates of a protein and assigns a hierarchical definition of secondary structure elements to the protein. <ref name="dssp">Kabsch W. and Sander C.. "[Dictionary of protein secondary structure: pattern recognition of hydrogen-bonded and geometrical features.]". Biopolymers, 1983</ref>

Results and Discussion

We predicted secondary structure of Arylsulfatase A with PSI-BLAST and Jpred3 using the Ebserver user interface. Further on, we downloaded the DSSP secondary structure assignment. DSSP assigns a hiearchical definition of secondary structure and therefore the assignment contains more structural classes than the 3 class prediction (H=helix, E=sheet, C=coil) of PSI-PRED and Jpred. To be able to compare the predictions to the assignemnt of DSSP, we converted the DSSP output classes to the three letter classification, using a perl script. The following table depicts DSSP classes, their description and the "3-letter-class", we converted it to.

DSSP class Description ' 3-letter class
H Helix H
G 3-10 Helix H
I Phi-Helix H
B single bridge E
E beta sheet E
T turn C
S bend C
\s coil C

Both methods yield similar predictions. The following figure shows a schematic representation of the prediction. Besides, it depicts the true positive prediction - i.e. the same class was predicted by the method and assigned by DSSP - in green.

Structure comparison.jpeg

The actual predictions and the DSSP assignment are listed below. Missing residues in the DSSP output are marked by an "m".

mmmmmmmmmmmmmmmmmmCCCEEEEEEECCCCCCCCHHHCCCCCCCHHHHHHHHCCEEECCEECCCCCHHHHHHHHHHCCCHHHHCC (DSSP)
CCHHHHHHHHHHHCCCCCCCCCEEEEEEECCCCCCCCCCCCCCCCCHHHHHHHHCCCEECCCCCCCCCCHHHHHHHHHCCCCCCCCC (JPRED)
CCHHHHHHHHHHHHCCCCCCCCEEEEEECCCCCCCCCCCCCCCCCCCHHHHHHHCCCCCCCCCCCCCCCHHHHHHHHHCCCCCCCCC (PSI-PRED)

CCCCCCCCECCECCCCCCCHHHHHHCCCCEEEEEECCCCECCHHHCCCHHHHCCCEEEECCCCCCCCECCCCEEECCCEECCCCECC (DSSP)
CCCCCCCCCCCCCCCCCCHHHHHHHCCCCEEEEEECCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC (JPRED)
CCCCCCCCCCCCCCCCCCCHHHHHHHCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC (PSI-PRED)

CCCCCCEEECCEEEEECCCHHHHHHHHHHHHHHHHHHHHHCCCCEEEEEECCCCCCCCCCCCCCCCCCCCHHHHHHHHHHHHHHHHH (DSSP)
CCCCCCCCCCCCCCCCCCCCCCCCCHHHHHHHHHHHHCCCCCCCCCCCCCCCCCCCCCCCCCCCCCHHHHHHHHHHHHHHHHHHHHH (JPRED)
CCCCCCCCCCCCCCCCCCCCCCHHHHHHHHHHHHHHHHCCCCCCEEEEECCCCCCCCCCCCCCCCCCCCCCHHHHHHHHHHHHHHHH (PSI-PRED)

HHHHHHCCCHHHEEEEEEECCCCCHHHHHHCCCCCCCCCCCCCCCHHHHECCCEEECCCCCCCEEECCCEEHHHHHHHHHHHHCCCC (DSSP)
HHHHHHCCCCCCEEEEEEECCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCEEEEEECCCCCCCCCECCCCCCCCHHHHHHHHHCCCC (JPRED)
HHHHHHCCCCCCEEEEECCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCEEEEEEECCCCCCCCEECCCHHHHHHHHHHHHHHCCCC (PSI-PRED)

CCCCCCCCCCHHHHHCCCCCCCCEEEECCCCCCCCCCCCEEEECCEEEEEEECCCHHHCCCCCHHHCCCCCCEEEEEEEEEECCCCC (DSSP)
CCCCCCCCCCCCCCCCCCCCCCCEEEEECCCCCCCCCCEEEEECCCEEEECCCCCCCCCCCCCCCCCCCCCCCCCCCCCEECCCCCC (JPRED)
CCCCCCCCCCHHHHCCCCCCCCCEEEECCCCCCCCCCEEEEEECCCEEEEECCCCCCCCCCCCCCCCCCCCCCCCCCCEEEECCCCC (PSI-PRED)

CCCCCCCCCmmmCCHHHHHHHHHHHHHHHHHHHHCCCCCCCHHHCECHHHCCCCCCCCCCCCCCCCECmmmm (DSSP)
CCCCCCCCCCHHHHHHHHHHHHHHHHHHHHHCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC (JPRED)
CCCCCCCCCCCCCHHHHHHHHHHHHHHHHHHCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC (PSI-PRED)

Both methods show a good performance on the main part of the protein with an overall accurcy of 74 % for PSI-PRED and an accuracy of 71 % for Jpred3. Thus, the accuracy (Q3) in this prediction is around 10 % lower than the average Q3 scores in the original publications of PSI-PRED and Jpred. Both methods predict the wrong secondary structure for the region from around position 110-200. DSSP assigns very short helices and beta sheets in this regions. Perhaps these are too short for a proper prediction. It is also remarkable, that the scores within this false predicted region are as high as for the rest of the protein sequence.

Prediction and confidence scores for PSI-PRED.
Confidence scroes of the Jpred prediction.


Program #TP #FP accuracy
PSI-PRED 374 133 0.74
Jpred 359 148 0.71


Prediction of Disordered Regions

Three different servers were challenged to predict disordered regions in ARSA, but no region was found that is consistent between the three methods.

DISOPRED

Output of Disopred showing the probability of being disordered along the sequence
DISOPRED predictions for a false positive rate threshold of: 2%

conf: 930000000000012210000000000000000000000000000000000000000000
pred: *...........................................................
  AA: MGAPRSLLLALAAGLAVARPPNIVLIFADDLGYGDLGCYGHPSSTTPNLDQLAAGGLRFT
              10        20        30        40        50        60

conf: 000000000000000000000000000000000000000000000000000000000000
pred: ............................................................
  AA: DFYVPVSLCTPSRAALLTGRLPVRMGMYPGVLVPSSRGGLPLEEVTVAEVLAARGYLTGM
              70        80        90       100       110       120

conf: 000000000000000000000000000000000000000000000000000000000000
pred: ............................................................
  AA: AGKWHLGVGPEGAFLPPHQGFHRFLGIPYSHDQGPCQNLTCFPPATPCDGGCDQGLVPIP
             130       140       150       160       170       180

conf: 000000000000000000000000000000000000000000000000000000000000
pred: ............................................................
  AA: LLANLSVEAQPPWLPGLEARYMAFAHDLMADAQRQDRPFFLYYASHHTHYPQFSGQSFAE
             190       200       210       220       230       240

conf: 000000000000000000000000000000000000000000000000000000000000
pred: ............................................................
  AA: RSGRGPFGDSLMELDAAVGTLMTAIGDLGLLEETLVIFTADNGPETMRMSRGGCSGLLRC
             250       260       270       280       290       300

conf: 000000000000000000000000000000000000000000000000000000000000
pred: ............................................................
  AA: GKGTTYEGGVREPALAFWPGHIAPGVTHELASSLDLLPTLAALAGAPLPNVTLDGFDLSP
             310       320       330       340       350       360

conf: 000000000000000000000000000000000000000000000000000000000000
pred: ............................................................
  AA: LLLGTGKSPRQSLFFYPSYPDEVRGVFAVRTGKYKAHFFTQGSAHSDTTADPACHASSSL
             370       380       390       400       410       420

conf: 000000000000000000000000000000000000000000000000000000000000
pred: ............................................................
  AA: TAHEPPLLYDLSKDPGENYNLLGGVAGATPEVLQALKQLQLLKAQLDAAVTFGPSQVARG
             430       440       450       460       470       480

conf: 000000000000000002571699999
pred: ......................*****
  AA: EDPALQICCHPGCTPRPACCHCPDPHA
             490       500

Asterisks (*) represent disorder predictions and dots (.) 
prediction of order. The confidence estimates give a rough
indication of the probability that each residue is disordered.

As you can see, only the first residue and the five last residues are predicted to be in a disordered region. The confidence for not being disordered is very clear: only for the last ten residues there is a uncertainty.

POODLE

plot of POODLE-output showing the probability of being disordered along the sequence


POODLE predicts many disordered residues. Depending on the treshold one can identify 6 or more disordered regions.

IUPred

The three different options of prediction were tried and are illustrated below. In general, IUPred did not predict any disordered region with a "Disorder tendency" above 0.6 except one very short region around residue 415 with the "long disorder"-option.

long disorder

The main profile of our server is to predict context-independent global disorder that encompasses at least 30 consecutive residues of predicted disorder. For this application the sequential neighbourhood of 100 residues is considered. <ref name="IUPred"> http://iupred.enzim.hu/Help.html</ref>

IUPred-output showing the probability of being disordered along the sequence with "long disorder"-option


short disorder

It uses a parameter set suited for predicting short, probably context-dependent, disordered regions, such as missing residues in the X-ray structure of an otherwise globular protein. For this application the sequential neighbourhood of 25 residues is considered. As chain termini of globular proteins are often disordered in X-ray structures, this is taken into account by an end-adjustment parameter which favors disorder prediction at the ends. <ref name="IUPred"> http://iupred.enzim.hu/Help.html</ref>

IUPred-output showing the probability of being disordered along the sequence with "short disorder"-option
structured domains

The dependable identification of ordered regions is a crucial step in target selection for structural studies and structural genomics projects. Finding putative structured domains suitable for stucture determination is another potential application of this server. In this case the algorithm takes the energy profile and finds continuous regions confidently predicted ordered. Neighbouring regions close to each other are merged, while regions shorter than the minimal domain size of at least 30 residues are ignored. When this prediction type is selected, the region(s) predicted to correspond to structured/globular domains are returned. <ref name="IUPred"> http://iupred.enzim.hu/Help.html</ref>

IUPred-output showing the probability of being disordered along the sequence with "structured domains"-option

Meta-Disorder

PredictProtein needs a registration which I tried, but it does not work: "username does not exist!"

Prediction of transmembrane alpha-helices and signal peptides

The prediction of membrane proteins and their topology is very important, because the experimental determination of these protein is quite challenging. It is very dificult to determine the structure, because the influence of membrane mimetic environments might lead to non-native structures and thus lead to a wrongf structural model of the protein. <ref>Cross, Timothy, Mukesh Sharma, Myunggi Yi, Huan-Xiang Zhou (2010). "Influence of Solubilizing Environments on Membrane Protein Structures"</ref>

SignalP

ARS A A4 RET4 INSL5 LAMP1 BACR
ARSA.jpeg A4.jpeg RET4.jpeg INSL5.jpeg LAMP1.jpeg BACR.jpeg


TMHMM

TMHMM predicts transmembrane helices (TMH) using a Hidden Markov Model (HMM). The protein described by TMH model essentially consists of seven different states. Globular domains can occur on the cytoplasmic and the non-cytoplasmic side. On the cytoplsmic side, globular domains are linked to loops, ehich are agin linked to cytoplasimc caps. These caps are followed by the helex core and there is again a cap on the non-cytoplasmic side. These caps are linked to globular domains by either short or long non-cytoplasmic loops.
TMHMM outputs the most likely structure of the protein, ragarding to the above model. It also includes the orientation (cytoplasmic or non-cytoplasmic side) of the N-terminal signal sequence. The ouput consists of a plot - graphically showing the different states along the protein - and some additional statistics <ref> http://www.cbs.dtu.dk/services/TMHMM-2.0/TMHMM2.0.guide.html#output </ref>:

  • The number of predicted transmembrane helices.
  • The expected number of amino acids in transmembrane helices. If this number is larger than 18 it is very likely to be a transmembrane protein (OR have a signal peptide).
  • The expected number of amino acids in transmembrane helices in the first 60 amino acids of the protein. If this number more than a few, you should be warned that a predicted transmembrane helix in the N-term could be a signal peptide.
  • The total probability that the N-term is on the cytoplasmic side of the membrane.


Protein #predicted TMHs #expected AAs in TMHs #expected AAs in TMHs in first 60 positions orientation (N-term at non-cyto. side) Graphical output
ARS A 0 2.65106 2.63079 0.12149 Sp P15289 ARSA HUMAN.gif
A4_HUMAN 1 22.72525 0.0027 0.00015 Sp P05067 A4 HUMAN.gif
INSL5_HUMAN 0 0.50415 0.50415 0.03772 Sp Q9Y5Q6 INSL5 HUMAN.gif
LAMP1_HUMAN 2 44.89582 22.24286 0.99287 Sp P11279 LAMP1 HUMAN.gif
RET4_HUMAN 0 0.01196 0.01179 0.01909 Sp P02753 RET4 HUMAN.gif
BACR 6 140.4032 26.1196 0.01887 Sp P02945 BACR HALSA.gif


Discussion
  • ARS A:outside 1 507 (=all)
  • A4_HUMAN: The topology is given below
Description Position '
outside 1-700
TMhelix 701-723
inside 724-770
  • INSL5_HUMAN: outside 1 135 (all residues)
  • LAMP1_HUMAN POSSIBLE N-term signal sequence
Description Position '
inside 1-10
TMhelix 11-33
outside 34-383
TMhelix 384-406
inside 407-417
  • RET4_HUMAN: outside 1 201 (all)
  • BACR:
  1. sp_P02945_BACR_HALSA POSSIBLE N-term signal sequence
Description Position '
outside 1-22
TMhelix 23-42
inside 43-54
TMhelix 55-77
outside 78-91
TMhelix 92-114
inside 115-120
TMhelix 121-143
outside 144-147
TMhelix 148-170
inside 171-189
TMhelix 190-212
outside 213-262

Phobius and Polyphobius

Protein Phobius - graphical Phobius - textual Polyphobius - graphical Polyphobius - textual
A4 Leuko A4 phobius.png FT SIGNAL 1 17

FT REGION 1 1 N-REGION.
FT REGION 2 12 H-REGION.
FT REGION 13 17 C-REGION.
FT TOPO_DOM 18 700 NON CYTOPLASMIC.
FT TRANSMEM 701 723
FT TOPO_DOM 724 770 CYTOPLASMIC.

Leuka A4 polyphobius.png FT SIGNAL 1 17

FT REGION 1 3 N-REGION.
FT REGION 4 12 H-REGION.
FT REGION 13 17 C-REGION.
FT TOPO_DOM 18 700 NON CYTOPLASMIC.
FT TRANSMEM 701 723
FT TOPO_DOM 724 770 CYTOPLASMIC.

ARS A Leuko arsa phobius.png FT SIGNAL 1 28

FT REGION 1 6 N-REGION.
FT REGION 7 18 H-REGION.
FT REGION 19 28 C-REGION.
FT TOPO_DOM 29 507 NON CYTOPLASMIC.

Leuka arsa polyphobius.png FT SIGNAL 1 16

FT REGION 1 4 N-REGION.
FT REGION 5 12 H-REGION.
FT REGION 13 16 C-REGION.
FT TOPO_DOM 17 507 NON CYTOPLASMIC.

BACR Leuko bacr phobius.png FT TOPO_DOM 1 22 NON CYTOPLASMIC.

FT TRANSMEM 23 42
FT TOPO_DOM 43 53 CYTOPLASMIC.
FT TRANSMEM 54 76
FT TOPO_DOM 77 95 NON CYTOPLASMIC.
FT TRANSMEM 96 114
FT TOPO_DOM 115 120 CYTOPLASMIC.
FT TRANSMEM 121 142
FT TOPO_DOM 143 147 NON CYTOPLASMIC.
FT TRANSMEM 148 169
FT TOPO_DOM 170 189 CYTOPLASMIC.
FT TRANSMEM 190 212
FT TOPO_DOM 213 217 NON CYTOPLASMIC.
FT TRANSMEM 218 237
FT TOPO_DOM 238 262 CYTOPLASMIC.

Leuko bacr polyphobius.png FT TOPO_DOM 1 21 NON CYTOPLASMIC.

FT TRANSMEM 22 43
FT TOPO_DOM 44 54 CYTOPLASMIC.
FT TRANSMEM 55 77
FT TOPO_DOM 78 94 NON CYTOPLASMIC.
FT TRANSMEM 95 114
FT TOPO_DOM 115 120 CYTOPLASMIC.
FT TRANSMEM 121 141
FT TOPO_DOM 142 147 NON CYTOPLASMIC.
FT TRANSMEM 148 166
FT TOPO_DOM 167 186 CYTOPLASMIC.
FT TRANSMEM 187 205
FT TOPO_DOM 206 215 NON CYTOPLASMIC.
FT TRANSMEM 216 237
FT TOPO_DOM 238 262 CYTOPLASMIC.

INSL5 Leuko insl5 phobius.png FT SIGNAL 1 22

FT REGION 1 5 N-REGION.
FT REGION 6 17 H-REGION.
FT REGION 18 22 C-REGION.
FT TOPO_DOM 23 135 NON CYTOPLASMIC.

Leuko insl5 polyphobius.png FT SIGNAL 1 22

FT REGION 1 4 N-REGION.
FT REGION 5 16 H-REGION.
FT REGION 17 22 C-REGION.
FT TOPO_DOM 23 135 NON CYTOPLASMIC.

LAMP1 Leuko lamp1 phobius.png FT SIGNAL 1 28

FT REGION 1 10 N-REGION.
FT REGION 11 22 H-REGION.
FT REGION 23 28 C-REGION.
FT TOPO_DOM 29 381 NON CYTOPLASMIC.
FT TRANSMEM 382 405
FT TOPO_DOM 406 417 CYTOPLASMIC.

Leuko lamp1 polyphobius.png FT SIGNAL 1 28

FT REGION 1 9 N-REGION.
FT REGION 10 22 H-REGION.
FT REGION 23 28 C-REGION.
FT TOPO_DOM 29 381 NON CYTOPLASMIC.
FT TRANSMEM 382 405
FT TOPO_DOM 406 417 CYTOPLASMIC.

RET4 Leuko ret4 phobius.png FT SIGNAL 1 18

FT REGION 1 2 N-REGION.
FT REGION 3 13 H-REGION.
FT REGION 14 18 C-REGION.
FT TOPO_DOM 19 201 NON CYTOPLASMIC.

Leuko ret4 polyphobius.png FT SIGNAL 1 18

FT REGION 1 3 N-REGION.
FT REGION 4 13 H-REGION.
FT REGION 14 18 C-REGION.
FT TOPO_DOM 19 201 NON CYTOPLASMIC.

OCTOPUS and SPOCTOPUS

OCPTOPUS uses a combination of a Hidden Markov Model and neural network to predict the topology of a transmembrane protein. It uses BALST to create a sequence profile, whihc is then used by the neural network to predict the preference of the amino acids to be located within a transmembrane (M), interface (I), close loop (L) globular loop (G), inside (i) or outside (o). These scores are then passed to the HMM, which predicts the final states.
SPOCTOPUS extends the OCTOPUS algorithm with a preprocessing step. OCTOPUS does not predict signal peptides. The N-terminal targeting sequences mainly consist of hydrophobic residues and thus thier properties strongly resemble the transmembrane helices. Not considering the signal peptides in the prediction often leads to a false prediction of a transmembrane helix at the N-terminal domain. Therefore SPOCTOPUS extends the OCTOPUS algorithm with the prediction of signal peptide preference scores within the first 70 amino acids of the protein. The exact location of a potential signal peptide are then predicted by a HMM in OCTOPUS.


Protein OCTOPUS SPOCTOPUS
ARS A Octopus arsa leuko.png Spoctopus arsa leuko.png
A4 Octopus a4 leuko.png Spoctopus a4 leuko.png
RET4 Octopus ret4 leuko.png Spoctopus ret4 leuko.png
INSL5 Octopus insl5 leuko.png Spoctopus insl5 leuko.png
LAMP1 Octopus lamp1 leuko.png Spoctopus lamp1 leuko.png
BACR Octopus bacr leuko.png Spoctopus bacr leuko.png


TargetP

TargetP is used to predict the cellular localization of a protein. It combines the two methods ChloroP and SignalP. The following targeting sequences can be identified:

  • chloroplast transit peptide (cTP)
  • mitochondrial targeting peptide (mTP)
  • secretory pathway signal peptide (SP)

TargetP uses a neural network to calculate and outputs scores for each of the above subcellular targets. TargetP finally predicts the location with the highest score. In our case all proteins are predicted to be targeted to the secretory pathway (S). Results are shown below. Note, that cTP is not included in our predictions, as we only considered eukaryotic and bacterial proteins. Also note, that TargetP is trained on eukaryotic proteins and hence the prediction for the protein "BACR", which is bacterial does not make sense, because there are completely different pathways of localization and secretion in eukayotes and bacteria (e.g. bacteria do not have an endoplasmatic reticulum, Golgi-Apparatus or Lysosome). Nevertheless, we included it in our analysis to see if TargetP predicts finds any localization sequence in it or predicts "-" (= no localization signal found).

Protein mTP SP other prediction
ARS A 0.070 0.926 0.054 S
A4_HUMAN 0.035 0.937 0.084 S
INSL5_HUMAN 0.074 0.899 0.037 S
LAMP1_HUMAN 0.043 0.953 0.017 S
RET4_HUMAN 0.242 0.928 0.020 S
BACR (bacterial) 0.019 0.897 0.562 S
Discussion

All proteins are assigned to the secretory pathway.

  • Arylsulfatase A is a lysosomal enzyme. Therefore, the prediction is correct, as lysosomal proteins are guided there by the secretory pathway, via the endoplasmatic reticulum and the Golgi apparatus.
  • coming
  • coming
  • coming
  • coming
  • As described above, BACR is a bacterial protein. TargetP assigns, that this protein is also guided to the secretory pathway, which makes no sense as the bacterial protein secretion is different from eukaryotic secretion. Nevertheless, the prediction is much less obvious in this case, compared to the others. The "other" class - meaning that no targeting sequence is found in the protein gets a considerable high score in this prediction, hence the assignment to S is more questionable here.

SignalP

sudo /apps/signalp-3.0/signalp -t gram- ../BACR.fasta > BACR.signalp
sudo /apps/signalp-3.0/signalp -t euk ../ARSA.fasta > ARSA.signalp
sudo /apps/signalp-3.0/signalp -t euk ../A4.fasta > A4.signalp
sudo /apps/signalp-3.0/signalp -t euk ../LAMP1.fasta > LAMP1.signalp
sudo /apps/signalp-3.0/signalp -t euk ../INSL5.fasta > INSL5.signalp
sudo /apps/signalp-3.0/signalp -t euk ../RET4.fasta > RET4.signalp

Prediction of GO Terms

GOPET

GO-Terms for 6 different proteins were predicted. The results are shown below. Bold entries are GO-Terms which are really connected to the protein. <ref>http://www.ebi.ac.uk/QuickGO/</ref>

A4
GOid Confidence GO term
GO:0004866 87% endopeptidase inhibitor activity
GO:0004867 86% serine-type endopeptidase inhibitor activity
GO:0030568 83% plasmin inhibitor activity
GO:0030304 83% trypsin inhibitor activity
GO:0030414 82% peptidase inhibitor activity
GO:0005488 79% binding
GO:0005515 74% protein binding
GO:0046872 73% metal ion binding
GO:0003677 71% DNA binding
GO:0008201 70% heparin binding
GO:0008270 69% zinc ion binding
GO:0005507 69% copper ion binding
GO:0005506 67% iron ion binding
ARS A
GOid Confidence GO term
GO:0003824 97% catalytic activity
GO:0016787 96% hydrolase activity
GO:0008484 95% sulfuric ester hydrolase activity
GO:0004065 92% arylsulfatase activity
GO:0004098 89% cerebroside-sulfatase activity
GO:0003943 83% N-acetylgalactosamine-4-sulfatase activity
GO:0004773 82% steryl-sulfatase activity
GO:0004423 82% iduronate-2-sulfatase activity
GO:0008449 82% N-acetylglucosamine-6-sulfatase activity
GO:0047753 82% choline-sulfatase activity
GO:0018741 81% alkyl sulfatase activity
GO:0046872 63% metal ion binding
GO:0016250 61% N-sulfoglucosamine sulfohydrolase activity


BACR_HALSA
GOid Confidence GO term
GO:0005216 77% ion channel activity
GO:0008020 75% G-protein coupled photoreceptor activity
GO:0015078 60% hydrogen ion transmembrane transporter activity


INSL 5
GOid Confidence GO term
GO:0005179 80% hormone activity


LAMP 1
GOid Confidence GO term
GO:0004812 60% aminoacyl-tRNA ligase activity
GO:0005524 60% ATP binding


RET 4
GOid Confidence GO term
GO:0005488 90% binding
GO:0005501 81% retinoid binding
GO:0008289 80% lipid binding
GO:0019841 78% retinol binding
GO:0005215 78% transporter activity
GO:0016918 78% retinal binding
GO:0005319 69% lipid transporter activity
GO:0008035 60% high-density lipoprotein particle binding

Pfam

ProtFun 2.2

References

<references />