TMpred
From BioPerl
Contents |
Description
TMpred makes a prediction of membrane-spanning regions and their orientation TMpred. The algorithm is based on the statistical analysis of TMbase, a database of naturally occuring transmembrane proteins. The prediction is made using a combination of several weight-matrices for scoring.
Website
http://www.ch.embnet.org/software/TMPRED_form.html
Example
Input
>MY_PROTEIN_SEQ MKSAFSFLPNWPLAPDAIFWAGFALFAAGLCGELCYRAWRLPRITGYAVIGLVAGSFGFGVIDASTDDTSRLLVNVALGL LLFELGSRLDLRWIRRNPWLIASSLAEATLTFVLVLAVLLLLKVPGMIALVLAAIAISTSPAMVIQLKTELRAEGQVSQR LITLSALNSVYAVVLTKLVTSWLHQEAYGNVFATILQPIYLLAGSFIVAYLFARACNYLFRHVAATMRDEHSFVALFGLV VLAIAVAQVLKLSTMLTLLLAGIIVKNLEARPQLWPEHFGTAGWLLTVILFVLTLTSFEGQDIAAGGLIAGALIATRFLA KLVGVLAFAKPSGLGVKQGIALGVSLVPMSALAYLLVDDTYQLYPNFDPRLRAVVMCSIVVLQLIGPLVVYRSLSAVGER RDAS
Output
TMpred prediction output for : MY_PROTEIN_SEQ
Sequence: MKS...DAS length: 404
Prediction parameters: TM-helix length between 17 and 33
1.) Possible transmembrane helices
==================================
The sequence positions in brackets denominate the core region.
Only scores above 500 are considered significant.
Inside to outside helices : 11 found
from to score center
17 ( 17) 36 ( 36) 1906 28
44 ( 46) 62 ( 62) 1681 54
71 ( 71) 87 ( 87) 296 79
124 ( 124) 145 ( 143) 2130 134
161 ( 163) 179 ( 179) 923 171
192 ( 194) 216 ( 210) 1696 202
232 ( 234) 250 ( 250) 1803 242
278 ( 278) 298 ( 296) 1883 288
303 ( 305) 323 ( 321) 901 313
339 ( 339) 357 ( 357) 1372 347
373 ( 373) 391 ( 389) 1886 381
Outside to inside helices : 11 found
from to score center
17 ( 17) 36 ( 36) 2206 26
44 ( 46) 62 ( 62) 1731 54
72 ( 72) 91 ( 91) 838 82
124 ( 128) 147 ( 145) 1939 137
161 ( 161) 179 ( 179) 911 171
192 ( 194) 213 ( 210) 1893 202
231 ( 231) 250 ( 250) 2014 242
279 ( 279) 298 ( 296) 2013 288
300 ( 300) 320 ( 320) 1237 309
338 ( 338) 357 ( 354) 1456 346
371 ( 373) 390 ( 390) 1614 381
2.) Table of correspondences
============================
Here is shown, which of the inside->outside helices correspond
to which of the outside->inside helices.
Helices shown in brackets are considered insignificant.
A "+" symbol indicates a preference of this orientation.
A "++" symbol indicates a strong preference of this orientation.
inside->outside | outside->inside
17- 36 (20) 1906 | 17- 36 (20) 2206 ++
44- 62 (19) 1681 | 44- 62 (19) 1731
( 71- 87 (17) 296 ) | 72- 91 (20) 838 ++
124- 145 (22) 2130 + | 124- 147 (24) 1939
161- 179 (19) 923 | 161- 179 (19) 911
192- 216 (25) 1696 | 192- 213 (22) 1893 +
232- 250 (19) 1803 | 231- 250 (20) 2014 ++
278- 298 (21) 1883 | 279- 298 (20) 2013 +
303- 323 (21) 901 | 300- 320 (21) 1237 ++
339- 357 (19) 1372 | 338- 357 (20) 1456 +
373- 391 (19) 1886 ++ | 371- 390 (20) 1614
3.) Suggested models for transmembrane topology
===============================================
These suggestions are purely speculative and should be used with
EXTREME CAUTION since they are based on the assumption that
all transmembrane helices have been found.
In most cases, the Correspondence Table shown above or the
prediction plot that is also created should be used for the
topology assignment of unknown proteins.
2 possible models considered, only significant TM-segments used
*** the models differ in the number of TM-helices ! ***
-----> STRONGLY prefered model: N-terminus outside
11 strong transmembrane helices, total score : 17582
# from to length score orientation
1 17 36 (20) 2206 o-i
2 44 62 (19) 1681 i-o
3 72 91 (20) 838 o-i
4 124 145 (22) 2130 i-o
5 161 179 (19) 911 o-i
6 192 216 (25) 1696 i-o
7 231 250 (20) 2014 o-i
8 278 298 (21) 1883 i-o
9 300 320 (21) 1237 o-i
10 339 357 (19) 1372 i-o
11 371 390 (20) 1614 o-i
------> alternative model
10 strong transmembrane helices, total score : 16494
# from to length score orientation
1 17 36 (20) 1906 i-o
2 44 62 (19) 1731 o-i
3 124 145 (22) 2130 i-o
4 161 179 (19) 911 o-i
5 192 216 (25) 1696 i-o
6 231 250 (20) 2014 o-i
7 278 298 (21) 1883 i-o
8 300 320 (21) 1237 o-i
9 339 357 (19) 1372 i-o
10 371 390 (20) 1614 o-i
References
<biblio>
- TMpred K. Hofmann & W. Stoffel (1993) TMbase - A database of membrane spanning proteins segments
Biol. Chem. Hoppe-Seyler 374,166 </biblio>