tmap

 

Function

Displays membrane spanning regions

Description

This program predicts transmembrane segments in proteins, utilising the algorithm described in: "Persson, B. & Argos, P. (1994) Prediction of transmembrane segments in proteins utilising multiple sequence alignments J. Mol. Biol. 237, 182-192."

tmap reads in one or more aligned protein sequences.

Two sets of propensity values are then used for the calculations: one for the middle, hydrophobic portion and one for the terminal regions of the transmembrane sequence spans. Average propensity values are calculated for each position along the alignment, with the contribution from each sequence weighted according to its dissimilarity relative to the other aligned sequences.

Eight-residue segments are considered as potential cores of transmembrane segments and elongated if thier middle propensity values are above a threshold. End propensity values are also considered as stop signals. Only helices with a length of 15 to 29 residues are allowed and corrections for strictly conserved charged residues are made.

The method is more successful than predictions based upon single sequences alone.

The results are plotted on a graph and written to a text file.

Usage

Here is a sample session with tmap


% tmap tsw:opsd_human -out tmap.res -graph cps 
Displays membrane spanning regions

Created tmap.ps

Go to the input files for this example
Go to the output files for this example

Command line arguments

   Mandatory qualifiers:
  [-msf]               seqset     File containing a sequence alignment
   -graph              xygraph    Graph type

   Optional qualifiers:
   -outfile            outfile    Output file name

   Advanced qualifiers: (none)
   General qualifiers:
  -help                boolean    Report command line options. More
                                  information on associated and general
                                  qualifiers can be found with -help -verbose


Mandatory qualifiers Allowed values Default
[-msf]
(Parameter 1)
File containing a sequence alignment Readable sequences Required
-graph Graph type EMBOSS has a list of known devices, including postscript, ps, hpgl, hp7470, hp7580, meta, colourps, cps, xwindows, x11, tektronics, tekt, tek4107t, tek, none, null, text, data, xterm, png EMBOSS_GRAPHICS value, or x11
Optional qualifiers Allowed values Default
-outfile Output file name Output file tmap.res
Advanced qualifiers Allowed values Default
(none)

Input file format

tmap reads a protein sequence USA for one or more aligned sequences.

Input files for usage example

'tsw:opsd_human' is a sequence entry in the example protein database 'tsw'

Database entry: tsw:opsd_human

ID   OPSD_HUMAN     STANDARD;      PRT;   348 AA.
AC   P08100; Q16414;
DT   01-AUG-1988 (Rel. 08, Created)
DT   01-AUG-1988 (Rel. 08, Last sequence update)
DT   15-JUL-1999 (Rel. 38, Last annotation update)
DE   RHODOPSIN.
GN   RHO.
OS   Homo sapiens (Human).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Mammalia;
OC   Eutheria; Primates; Catarrhini; Hominidae; Homo.
RN   [1]
RP   SEQUENCE FROM N.A.
RX   MEDLINE; 84272729.
RA   NATHANS J., HOGNESS D.S.;
RT   "Isolation and nucleotide sequence of the gene encoding human
RT   rhodopsin.";
RL   Proc. Natl. Acad. Sci. U.S.A. 81:4851-4855(1984).
RN   [2]
RP   SEQUENCE OF 1-120 FROM N.A.
RA   BENNETT J., BELLER B., SUN D., KARIKO K.;
RL   Submitted (NOV-1994) to the EMBL/GenBank/DDBJ databases.
RN   [3]
RP   REVIEW ON ADRP VARIANTS.
RX   MEDLINE; 94004905.
RA   AL-MAGHTHEH M., GREGORY C., INGLEHEARN C., HARDCASTLE A.,
RA   BHATTACHARYA S.;
RT   "Rhodopsin mutations in autosomal dominant retinitis pigmentosa.";
RL   Hum. Mutat. 2:249-255(1993).
RN   [4]
RP   VARIANT ADRP HIS-23.
RX   MEDLINE; 90136922.
RA   DRYJA T.P., MCGEE T.L., REICHEI E., HAHN L.B., COWLEY G.S.,
RA   YANDELL D.W., SANDBERG M.A., BERSON E.L.;
RT   "A point mutation of the rhodopsin gene in one form of retinitis
RT   pigmentosa.";
RL   Nature 343:364-366(1990).
RN   [5]
RP   VARIANTS ADRP.
RX   MEDLINE; 91051574.
RA   FARRAR G.J., KENNA P., REDMOND R., MCWILLIAM P., BRADLEY D.G.,
RA   HUMPHRIES M.M., SHARP E.M., INGLEHEARN C.F., BASHIR R., JAY M.,
RA   WATTY A., LUDWIG M., SCHINZEL A., SAMANNS C., GAL A.,
RA   BHATTACHARYA S.S., HUMPHRIES P.;
RT   "Autosomal dominant retinitis pigmentosa: absence of the rhodopsin
RT   proline-->histidine substitution (codon 23) in pedigrees from
RT   Europe.";
RL   Am. J. Hum. Genet. 47:941-945(1990).
RN   [6]
RP   VARIANTS ADRP HIS-23; ARG-58; LEU-347 AND SER-347.
RX   MEDLINE; 91015273.


  [Part of this file has been deleted for brevity]

FT                                /FTId=VAR_004816.
FT   VARIANT     209    209       V -> M (EFFECT NOT KNOWN).
FT                                /FTId=VAR_004817.
FT   VARIANT     211    211       H -> P (IN ADRP).
FT                                /FTId=VAR_004818.
FT   VARIANT     211    211       H -> R (IN ADRP).
FT                                /FTId=VAR_004819.
FT   VARIANT     216    216       M -> K (IN ADRP).
FT                                /FTId=VAR_004820.
FT   VARIANT     220    220       F -> C (IN ADRP).
FT                                /FTId=VAR_004821.
FT   VARIANT     222    222       C -> R (IN ADRP).
FT                                /FTId=VAR_004822.
FT   VARIANT     255    255       MISSING (IN ADRP).
FT                                /FTId=VAR_004823.
FT   VARIANT     264    264       MISSING (IN ADRP).
FT                                /FTId=VAR_004824.
FT   VARIANT     267    267       P -> L (IN ADRP).
FT                                /FTId=VAR_004825.
FT   VARIANT     267    267       P -> R (IN ADRP).
FT                                /FTId=VAR_004826.
FT   VARIANT     292    292       A -> E (IN CSNB4).
FT                                /FTId=VAR_004827.
FT   VARIANT     296    296       K -> E (IN ADRP).
FT                                /FTId=VAR_004828.
FT   VARIANT     297    297       S -> R (IN ADRP).
FT                                /FTId=VAR_004829.
FT   VARIANT     342    342       T -> M (IN ADRP).
FT                                /FTId=VAR_004830.
FT   VARIANT     345    345       V -> L (IN ADRP).
FT                                /FTId=VAR_004831.
FT   VARIANT     345    345       V -> M (IN ADRP).
FT                                /FTId=VAR_004832.
FT   VARIANT     347    347       P -> A (IN ADRP).
FT                                /FTId=VAR_004833.
FT   VARIANT     347    347       P -> L (IN ADRP; COMMON VARIANT).
FT                                /FTId=VAR_004834.
FT   VARIANT     347    347       P -> Q (IN ADRP).
FT                                /FTId=VAR_004835.
FT   VARIANT     347    347       P -> R (IN ADRP).
FT                                /FTId=VAR_004836.
FT   VARIANT     347    347       P -> S (IN ADRP).
FT                                /FTId=VAR_004837.
SQ   SEQUENCE   348 AA;  38892 MW;  07443BEA CRC32;
     MNGTEGPNFY VPFSNATGVV RSPFEYPQYY LAEPWQFSML AAYMFLLIVL GFPINFLTLY
     VTVQHKKLRT PLNYILLNLA VADLFMVLGG FTSTLYTSLH GYFVFGPTGC NLEGFFATLG
     GEIALWSLVV LAIERYVVVC KPMSNFRFGE NHAIMGVAFT WVMALACAAP PLAGWSRYIP
     EGLQCSCGID YYTLKPEVNN ESFVIYMFVV HFTIPMIIIF FCYGQLVFTV KEAAAQQQES
     ATTQKAEKEV TRMVIIMVIA FLICWVPYAS VAFYIFTHQG SNFGPIFMTI PAFFAKSAAI
     YNPVIYIMMN KQFRNCMLTT ICCGKNPLGD DEASATVSKT ETSQVAPA
//

Output file format

Output files for usage example

Graphics File: tmap.ps

[tmap results]

File: tmap.res

Program TMAP, version 46, to predict transmembrane segments from .msf file.
The program reads a multiple alignment file of the GCG multiple sequence format
and predicts membrane-spanning regions according to the algorithm in
Persson & Argos (1994), J. Mol. Biol. 237, 182-192.

RESULTS from program TMAP, edition 46'

Numbers give: a) number of transmembrane segment
              b) start of TM segment (alignment position / residue number)
              c) end of TM segment (alignment position / residue number)
              d) length of TM segment within parentheses

PREDICTED TRANSMEMBRANE SEGMENTS FOR ALIGNMENT 

  TM  1:   43 -   69  (27.0)
  TM  2:   73 -   97  (25.0)
  TM  3:  112 -  140  (29.0)
  TM  4:  148 -  176  (29.0)
  TM  5:  201 -  229  (29.0)
  TM  6:  255 -  275  (21.0)
  TM  7:  282 -  302  (21.0)


PREDICTED TRANSMEMBRANE SEGMENTS FOR PROTEIN OPSD_HUMAN

  TM  1:   43 -   69 (27)
  TM  2:   73 -   97 (25)
  TM  3:  112 -  140 (29)
  TM  4:  148 -  176 (29)
  TM  5:  201 -  229 (29)
  TM  6:  255 -  275 (21)
  TM  7:  282 -  302 (21)


A plot of the propensities to form the middle and the end of transmembrane regions is output.

Bars are displayed in the plot above the regions predicted as being most likely to form transmembrane regions.

The text file (specified by the -outfile option) gives a summary of these regions.

The transmembrane regions for the complete alignment are given first, followed by the predictions for each individual sequence in the alignment. (There is only one sequence in the example alignment.)

Data files

None.

Notes

None.

References

"Persson, B. & Argos, P. (1994) Prediction of transmembrane segments in proteins utilsing multiple sequence alignments J. Mol. Biol. 237, 182-192."

Warnings

None.

Diagnostic Error Messages

None.

Exit status

0 if successful.

Known bugs

None.

See also

Program nameDescription
garnierPredicts protein secondary structure
helixturnhelixReport nucleic acid binding motifs
hmomentHydrophobic moment calculation
pepcoilPredicts coiled coil regions
pepnetDisplays proteins as a helical net
pepwheelShows protein sequences as helices

Author(s)

Original program by Bengt Persson and Patrick Argos.

This application was modified for inclusion in EMBOSS by Ian Longden (il@sanger.ac.uk) Informatics Division, The Sanger Centre, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.

History

Completed 17th June 1999.

Target users

This program is intended to be used by everyone and everything, from naive users to embedded scripts.

Comments