HMMERALIGN

Table of Contents

FUNCTION

DESCRIPTION

EXAMPLE

FUNCTION

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HmmerAlign uses a profile hidden Markov model (HMM) as a template to create an optimal multiple alignment of a group of sequences.

DESCRIPTION

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HmmerAlign provides a Accelrys GCG (GCG) interface to the hmmalign program of Dr. Sean Eddy's HMMER package. It allows you to access most of hmmalign's parameters from GCG command line or from its graphical interfaces.

HmmerAlign aligns one or more sequences to a profile HMM. It can be used as a very efficient way to align a large number of sequences. First align a small number of representative sequences with PileUp. Then create a profile HMM from this small alignment with HmmerBuild. (The profile does not need to be calibrated.) HmmerAlign uses this profile HMM as a "seed" alignment, to which any number of additional sequences can be quickly aligned. Aligning a large number of sequences this way is a lot more time efficient, than using PileUp to create the entire alignment.

EXAMPLE

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Here is a session using HmmerAlign to align three 75kd peptide sequences from Chlamydia trachomatis with the profile hidden Markov model created from 75kd heat shock and heat shock cognate peptide sequences in the HmmerBuild example session.

% hmmeralign

HMMERALIGN which profile HMM ? hsp70.hmm_g

to which group of sequences ? @75kd.list

What should the output file be called (* 75kd.msf *)?

Creating temp file for input to hmmalign.

Calling hmmalign to perform analysis ...

hmmalign - align sequences to an HMM profile

HMMER 2.1.1 (Dec 1998)

HMMER is freely distributed under the GNU General Public License (GPL).

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

HMM file: hsp70.hmm_g

Sequence file: /usr/users/share/smith/@75kd.list

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

OUTPUT

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Here is the output file:

!!AA_MULTIPLE_ALIGNMENT 1.0

Author:       HMMER 2.1.1

 75kd.msf  MSF: 691  Type: P  July 10, 2000 14:10  Check: 2734 ..

 Name: A40158           Len:   691  Check:  199  Weight:  1.00

 Name: S10435           Len:   691  Check:  199  Weight:  1.00

 Name: S16159           Len:   691  Check: 2336  Weight:  1.00

//

        1                                                   50

A40158  msekRKSNKI IGIDLGTTNS CVSVMEGGQP KVIASSEGTR TTPSIVAFKG

S10435  msekRKSNKI IGIDLGTTNS CVSVMEGGQP KVIASSEGTR TTPSIVAFKG

S16159  msehKKSSKI IGIDLGTTNS CVSVMEGGQA KVITSSEGTR TTPSIVAFKG

        51                                                 100

A40158  GETLVGIPAK RQAVTNPEKT LASTKRFIGR KFS..EVESE IKTVPYKVAP

S10435  GETLVGIPAK RQAVTNPEKT LASTKRFIGR KFS..EVESE IKTVPYKVAP

S16159  NEKLVGIPAK RQAVTNPEKT LGSTKRFIGR KYS..EVASE IQTVPYTVTS

        101                                                150

A40158  NSKGDAVFDV ....EQKLYT PEEIGAQILM KMKETAEAYL GETVTEAVIT

S10435  NSKGDAVFDV ....EQKLYT PEEIGAQILM KMKETAEAYL GETVTEAVIT

S16159  GSKGDAVFEV ....DGKQYT PEEIGAQILM KMKETAEAYL GETVTEAVIT

        151                                                200

A40158  VPAYFNDSQR ASTKDAGRIA GLDVKRIIPE PTAAALAYGI DK....EGDK

S10435  VPAYFNDSQR ASTKDAGRIA GLDVKRIIPE PTAAALAYGI DK....EGDK

S16159  VPAYFNDSQR ASTKDAGRIA GLDVKRIIPE PTAAALAYGI DK....VGDK

        201                                                250

A40158  KIAVFDLGGG TFDISILEIG .DGVFEVLST NGDTHLGGDD FDGVIINWML

S10435  KIAVFDLGGG TFDISILEIG .DGVFEVLST NGDTHLGGDD FDGVIINWML

S16159  KIAVFDLGGG TFDISILEIG .DGVFEVLST NGDTLLGGDD FDEVIIKWMI

        251                                                300

A40158  DEFK.KQEGI DLSKDNMALQ RLKDAAEKAK IELSGVSSTE INQPFITIDA

S10435  DEFK.KQEGI DLSKDNMALQ RLKDAAEKAK IELSGVSSTE INQPFITIDA

S16159  EEFK.KQEGI DLSKDNMALQ RLKDAAEKAK IELSGVSSTE INQPFITMDA

        301                                                350

A40158  NGPKHLALTL TRAQFEHLAS SLIERTKQPC AQALKDAKLS ASDIDDVLLV

S10435  NGPKHLALTL TRAQFEHLAS SLIERTKQPC AQALKDAKLS ASDIDDVLLV

S16159  QGPKHLALTL TRAQFEKLAA SLIERTKSPC IKALSDAKLS AKDIDDVLLV

        351                                                400

A40158  GGMSRMPAVQ AVVKEIF.GK EPNKGVNPDE VVAIGAAIQG GVLGGE....

S10435  GGMSRMPAVQ AVVKEIF.GK EPNKGVNPDE VVAIGAAIQG GVLGGE....

S16159  GGMSRMPAVQ ETVKELF.GK EPNKGVNPDE VVAIGAAIQG GVLGGE....

        401                                                450

A40158  .VKDVLLLDV IPLSLGIETL GGVMTPLVER NTTIPTQKKQ IFSTAADNQP

S10435  .VKDVLLLDV IPLSLGIETL GGVMTPLVER NTTIPTQKKQ IFSTAADNQP

S16159  .VKDVLLLDV IPLSLGIETL GGVMTTLVER NTTIPTQKKQ IFSTAADNQP

        451                                                500

A40158  AVTIVVLQGE RPMAKDNKEI GRFDLTDIPP APRGHPQIEV TFDIDANGIL

S10435  AVTIVVLQGE RPMAKDNKEI GRFDLTDIPP APRGHPQIEV TFDIDANGIL

S16159  AVTIVVLQGE RPMAKDNKEI GRFDLTDIPP APRGHPQIEV SFDIDANGIF

        501                                                550

A40158  HVSAKDAASG REQKIRIEAS SG.LKEDEIQ QMIRDAELHK EEDKQRKEAS

S10435  HVSAKDAASG REQKIRIEAS SG.LKEDEIQ QMIRDAELHK EEDKQRKEAS

S16159  HVSAKDVASG KEQKIRIEAS SG.LQEDEIQ RMVRDAEINK EEDKKRREAS

        551                                                600

A40158  DVKNEADGMI FRAEKAVKD. .YHDKIPAEL VKEIEEHIEK VRQAIK...E

S10435  DVKNEADGMI FRAEKAVKD. .YHDKIPAEL VKEIEEHIEK VRQAIK...E

S16159  DAKNEADSMI FRAEKAIKD. .YKEQIPETL VKEIEERIEN VRNALKDD..

        601                                                650

A40158  DASTTAIKAA SDELSTRMQK IG.EAMQAQS ASAAAS.SAA NAQGG..PNI

S10435  DASTTAIKAA SDELSTRMQK IG.EAMQAQS ASAAAS.SAA NAQGG..PNI

S16159  .APIEKIKEV TEDLSKHMQK IG.ESMQ.SQ SASAAAsSAA NAKGG..PNI

        651                                       691

A40158  NSEDLKKHSF STRPPAG..G SASSTDNIED ADveivdkpe .

S10435  NSEDLKKHSF STRPPAG..G SASSTDNIED ADveivdkpe .

S16159  NTEDLKKHSF STK...PPSN NGSSEDHIEE ADveiidndd k

In the output, uppercase letters represent residues that align to a consensus position in the original alignment (corresponding to a match state in the model). Lowercase letters are used to represent inserted residues. Periods represent gaps.

INPUT FILES

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HmmerAlign takes a profile HMM as one of its inputs. You can create a profile HMM from a sequence alignment with the HmmerBuild program. You can also obtain a profile HMM of a known protein family from the Pfam database using HmmerFetch.

HmmerAlign's other input is a valid GCG sequence specification -- either a single sequence or a multiple file specification. If the multiple file specification represents a sequence alignment (such as an MSF file), HmmerAlign ignores the existing alignment unless you use the -HEURISTICalignmentparameter or you use the -MAPAlignment parameter with the aligned sequences from which the profile HMM was built. You can specify multiple sequences in a number of ways: by using a list file, for example@project.list; by using an MSF or RSF file, for example project.msf{*}; or by using a sequence specification with an asterisk (*) wildcard, for example GenBank:*.

The function of HmmerAlign depends on whether your input sequence(s) are protein or nucleotide. Programs determine the type of a sequence by the presence of either Type: N or Type: P on the last line of the text heading just above the sequence. If your sequence(s) are not the correct type, turn to Appendix VI for information on how to change or set the type of a sequence.

RELATED PROGRAMS

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PileUp creates a multiple sequence alignment from a group of related sequences. Pretty displays multiple sequence alignments.

ProfileMake makes a profile from a multiple sequence alignment. ProfileSearch uses the profile to search a database for sequences with similarity to the group of aligned sequences. ProfileSegments displays optimal alignments between each sequence in the ProfileSearch output list and the group of aligned sequences (represented by the profile consensus). ProfileGap makes optimal alignments between one or more sequences and a group of aligned sequences represented as a profile. ProfileScan finds structural and sequence motifs in protein sequences, using predetermined parameters to determine significance.

HmmerBuild makes a profile hidden Markov model from a multiple sequence alignment. HmmerAlign aligns one or more sequences to a profile HMM. HmmerPfam searches a database of profile HMMs with a sequence query in order to identify known domains within the sequence. HmmerSearch uses a profile HMM as a query to search a sequence database for sequences similar to the original aligned sequences. HmmerCalibrate calibrates a hidden Markov model so that database searches using it as a query will be more sensitive. HmmerIndex creates a binary GSI ("generic sequence index") for a database of profile HMMs. HmmerFetch retrieves a profile hidden Markov model by name from an indexed database of profile HMMs. HmmerEmit randomly generates sequences that match a profile HMM. HmmerConvert converts between different profile HMM file formats and from profile HMM to GCG profile file format.

MEME finds conserved motifs in a group of unaligned sequences and saves these motifs as a set of profiles. You can search a database of sequences with these profiles using the MotifSearch program.

RESTRICTIONS

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The MSF file format can accomodate a maximum of 500 sequences. If the final alignment will contain more than 500 sequences, use the -RSF parameter to output the results in RSF format.

ALGORITHM

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See the Profile HMM Analysis Essay for an introduction to profile hidden Markov models and the terminology associated with them.

HmmerAlign uses the Viterbi algorithm to align each sequence to the profile HMM. This is a dynamic programming algorithm that determines which residues in the sequence correspond to match states in the model (consensus columns in the original alignment). Residues in the sequence that do not correspond to match states in the model are displayed as insertions in the alignment. If the sequence is missing a residue where the model specifies a match state, a gap character is put into the alignment.

The alignment is built recursively by finding optimal subalignments of each new sequence to the profile HMM until part of the sequence or the entire sequence is optimally aligned to the entire profile HMM. If the profile HMM is set to allow local alignments, the final alignment can start at any match state in the model and stop at any subsequent match state.

For more information on how the Viterbi algorithm is used with profile HMMs, see section 5.4, "Searching with profile HMMs," in Section 5 of Biological Sequence Analysis by Richard Durbin, et al. (Cambridge University Press, 1998).

By default, the input sequences are displayed aligned to each other, based on their alignments to the same profile HMM. To display the input sequences aligned to the original alignment (from which the profile HMM was built), use the -MAPAlignment parameter. If you would like to align the input sequences to some other alignment (not the one that was used to build the profile HMM) using the profile HMM as a seed, use the -HEURISTICaligment parameter.

For more information, see Eddy, et al. (Curr. Opin. Struct. Biol., 6; 361-365 (1996)) and the Eddy lab website athttp://hmmer.wustl.edu/.

COMMAND-LINE SUMMARY

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All parameters for this program may be added to the command line. Use -CHEck to view the summary below and to specify parameters before the program executes. In the summary below, the capitalized letters in the parameter names are the letters that you must type in order to use the parameter. Square brackets ([ and ]) enclose parameter values that are optional.

Minimal Syntax: % hmmeralign [-INfile1=]hsp70.hmm_g [-INfile2=]@75kd.list

 -Default

Prompted Parameters:

[-OUTfile=]75kd.msf names the output file

Local Data Files: None

Optional Parameters:

-BEGin1=1 -END1=100 sets the range of interest for each sequence

-MATch includes in the alignment only those residues that

align to consensus positions

-MAPAlignment=a.msf{*} reads an alignment from a.msf and aligns it as a

single object to the HMM using a "map" kept

in the HMM.

-MAPBegin=1 sets the beginning coordinate for the alignment

-MAPEnd=100 sets the ending coordinate for the alignment

-HEURISTICalignment=a.msf{*} reads an alignment from a.msf and aligns it as a

single object to the HHM using a heuristic

programming procedure

-RSF saves the output file in RSF format

-NOMONitor suppresses the screen trace of program progress

LOCAL DATA FILES

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None.

PARAMETER REFERENCE

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You can set the parameters listed below from the command line.

Following some of the parameters described below is a short expression in parentheses. These are the names of the corresponding parameters used in the native HMMER package. Some of the GCG parameters are identical to the original HMMER parameters, others have been changed to fit GCG's conventions.

-BEGin=1

Sets the beginning position for all sequences. When beginning positions are specified for individual sequences in a list file, HmmerAlign ignores the -BEGin parameter.

-END=100

Sets the ending position for all sequences. When ending positions are specified for individual sequences in a list file, HmmerAlign ignores the -END parameter.

-MATch (-m)

Includes in the alignment only those symbols that align to match states in the profile HMM (consensus positions in the original alignment). Inserted symbols will not be shown. Instead, one or more consecutive insert symbols are replaced with a single '*'.

-MAPAlignment=a.msf{*} (--mapali a.msf)

Aligns the profile HMM onto an existing alignment, which must be the alignment from which the profile HMM was built. The profile HMM is "mapped" onto this alignment, allowing you to view the model in the context of the original aligned sequences. Because the map is stored with the profile HMM, this procedure is quite fast, and the results are consistent with the way the profile HMM was constructed.

-MAPBegin=1

Sets the beginning position for all sequences in the alignment file. When beginning positions are specified for individual sequences in a list file, HmmerAlign ignores the -MAPBegin parameter.

-MAPEnd=100

Sets the ending position for all sequences in the alignment file. When ending positions are specified for individual sequences in a list file, HmmerAlign ignores the -MAPEnd parameter.

-HEURISTICalignment=a.msf{*} (--withali a.msf)

With this option the program does not only align the input sequences to the profile HMM. It also, using a heuristic (nonoptimal) dynamic programming procedure, compares the profile HMM to the fixed alignment specified with this parameter in order to find the best location for the merging of the two alignments. Finally it displays the results as one alignment. The aligned input sequences and the fixed alignment have both been compared to the profile HMM but not to each other. This may be slow and is not guaranteed to produce results that are completely consistent with the way the profile HMM was constructed. Unlike the -MAPAlignment parameter, -HEURISTICalignment can be used for any alignment, not just the one from which the model was built.

-RSF

Saves the output file in RSF format instead of the default MSF format. This is necessary if the final alignment will contain more than the 500 sequence maximum imposed by the MSF format.

-NOMONitor

Suppresses the display of the program's progress on the screen.

Printed: May 27, 2005 12:39

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