clustalw.py

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from ost.bindings import utils
from ost import settings, io, seq, LogError
import os
import subprocess

def ClustalW(seq1, seq2=None, clustalw=None, keep_files=False, nopgap=False, 
             clustalw_option_string=False):
  '''
  Runs a ClustalW multiple sequence alignment. The results are returned as a
  :class:`~ost.seq.AlignmentHandle` instance.
  
  There are two ways to use this function:
  
   - align exactly two sequences:
   
      :param seq1: sequence_one
      :type seq1: :class:`~ost.seq.SequenceHandle` or :class:`str`
      
      :param seq2: sequence_two
      :type seq2: :class:`~ost.seq.SequenceHandle` or :class:`str`
  
      The two sequences can be specified as two separate function parameters 
      (`seq1`, `seq2`). The type of both parameters can be either
      :class:`~ost.seq.SequenceHandle` or :class:`str`, but must be the same for
      both parameters.
      
   - align two or more sequences:
   
      :param seq1: sequence_list
      :type seq1: :class:`~ost.seq.SequenceList`
      
      :param seq2: must be :class:`None`
      
      Two or more sequences can be specified by using a
      :class:`~ost.seq.SequenceList`. It is then passed as the first function 
      parameter (`seq1`). The second parameter (`seq2`) must be :class:`None`.
      
       
  :param clustalw: path to ClustalW executable (used in :func:`~ost.settings.Locate`)
  :type clustalw: :class:`str`
  :param nopgap: turn residue-specific gaps off
  :type nopgap: :class:`bool`
  :param clustalw_option_string: additional ClustalW flags (see http://www.clustal.org/download/clustalw_help.txt)
  :type clustalw_option_string: :class:`str`
  :param keep_files: do not delete temporary files
  :type keep_files: :class:`bool`

  .. note ::
   
    - In the passed sequences ClustalW will convert lowercase to uppercase, and
      change all '.' to '-'. OST will convert and '?' to 'X' before aligning
      sequences with ClustalW.
    - If a :attr:`sequence name <ost.seq.SequenceHandle.name>` contains spaces,
      only the part before the space is considered as sequence name. To avoid
      surprises, you should remove spaces from the sequence name.
    - Sequence names must be unique (:class:`ValueError` exception raised
      otherwise).

  ClustalW will accept only IUB/IUPAC amino acid and nucleic acid codes:

  ======= ======================= ======= ============================ 
  Residue  Name                   Residue  Name 
  ======= ======================= ======= ============================
     A    alanine                    P    proline
     B    aspartate or asparagine    Q    glutamine
     C    cystine                    R    arginine
     D    aspartate                  S    serine
     E    glutamate                  T    threonine
     F    phenylalanine              U    selenocysteine
     G    glycine                    V    valine
     H    histidine                  W    tryptophan
     I    isoleucine                 Y    tyrosine
     K    lysine                     Z    glutamate or glutamine
     L    leucine                    X    any
     M    methionine                 \*   translation stop
     N    asparagine                 \-   gap of indeterminate length
  ======= ======================= ======= ============================ 

  '''
  clustalw_path=settings.Locate(('clustalw', 'clustalw2'), 
                                explicit_file_name=clustalw)
  
  if seq2!=None:
    if isinstance(seq1, seq.SequenceHandle) and isinstance(seq2, seq.SequenceHandle):
      seq_list=seq.CreateSequenceList()
      seq_list.AddSequence(seq1)
      seq_list.AddSequence(seq2)
    elif isinstance(seq1, str) and isinstance(seq2, str):
      seqh1=seq.CreateSequence("seq1", seq1)
      seqh2=seq.CreateSequence("seq2", seq2)
      seq_list=seq.CreateSequenceList()
      seq_list.AddSequence(seqh1)
      seq_list.AddSequence(seqh2)
    else:
      LogError("WARNING: Specify at least two Sequences")
      return
  elif isinstance(seq1, seq.SequenceList):
    seq_list=seq1
  else:
    LogError("WARNING: Specify either two SequenceHandles or one SequenceList")
    return

  sequence_names = set()
  for s in seq_list:
    # we cut out anything after a space to be consistent with ClustalW behaviour
    sequence_names.add(s.GetName().split(' ')[0])
  if len(sequence_names) < len(seq_list):
    raise ValueError("ClustalW can only process sequences with unique identifiers!")


  new_list = seq.CreateSequenceList()
  for s in seq_list:
    ss = s.Copy()
    for i,c in enumerate(ss):
      if c=='?':
        ss[i]='X'
    new_list.AddSequence(ss)

  seq_list = new_list

  
  temp_dir=utils.TempDirWithFiles((seq_list,))
  out=os.path.join(temp_dir.dirname, 'out.fasta')
  command='%s -infile="%s" -output=fasta -outfile="%s"' % (clustalw_path,
                                                           temp_dir.files[0],
                                                           out)
  if nopgap:
    command+=" -nopgap"
  if clustalw_option_string!=False:
    command=command+" "+clustalw_option_string  #see useful flags: http://toolkit.tuebingen.mpg.de/clustalw/help_params

  ps=subprocess.Popen(command, shell=True, stdout=subprocess.PIPE)
  ps.stdout.readlines()
  aln=io.LoadAlignment(out)
  

  for sequence in seq_list:
    for seq_num,aln_seq in enumerate(aln.sequences):
      if aln_seq.GetName()==sequence.GetName():
        break
    aln.SetSequenceOffset(seq_num,sequence.offset)
    if sequence.HasAttachedView():
      aln.AttachView(seq_num,sequence.GetAttachedView().Copy())

  if not keep_files:
    temp_dir.Cleanup()
  
  return aln