Package csb :: Package bio :: Package io :: Module vasco |
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# Source Code for Module csb.bio.io.vasco

      1  """
      2  VASCO Chemical Shift format parser.
      3  """
      4
      5  import csb.core
      6
      7
      8 -class ShiftInfo(object):
      9
     10 -    def __init__(self, residue_id, amino_acid, nucleus,
     11                   shift, element, secondary_structure):
     12
     13          self.residue_id = residue_id
     14          self.nucleus = nucleus
     15          self.element = element
     16          self.amino_acid = amino_acid
     17          self.shift = shift
     18          self.secondary_structure = secondary_structure
     19
     20 -    def __str__(self):
     21          return '{0.amino_acid} {0.nucleus} {0.shift}'.format(self)
     22
     23      __repr__ = __str__
     24
     25
     26 -class ChemicalShiftContainer(csb.core.DictionaryContainer):
     27
     28 -    def __init__(self, bmrb_id='', pdb_id='', sequence='',
     29                   chain='', exptype=''):
     30
     31          self.bmrb_id = bmrb_id
     32          self.pdb_id = pdb_id
     33          self.sequence = sequence
     34          self.chain = chain
     35          self.exptype = exptype
     36
     37          super(ChemicalShiftContainer, self).__init__()
     38
     39 -class VascoStructureParser(object):
     40      """
     41      Simple Vasco Parser
     42      """
     43
     44 -    def __init__(self):
     45          self._stream  = None
     46
     47 -    def parse(self, file_name, ignore_outliers=True):
     48          """
     49          @param file_name: source  file to parse
     50          @type file_name: str
     51          @return: a L{ChemicalShiftContainer} of L{ShiftInfo} objects
     52          @rtype: dict
     53          """
     54          self._stream  = open(file_name)
     55          shifts = self._parse_header()
     56
     57          self._parse_shifts(shifts, ignore_outliers=ignore_outliers)
     58          self._stream.close()
     59
     60          return shifts
     61
     62 -    def _parse_header(self):
     63
     64          bmrb_id = ''
     65          pdb_id = ''
     66          sequence = ''
     67          chain = ''
     68          exptype = ''
     69          self._stream.seek(0)
     70
     71          while True:
     72              try:
     73                  line = next(self._stream)
     74              except StopIteration :
     75                  break
     76
     77              if line.startswith('#'):
     78                  if line[2:].startswith('BMRB ORIGIN'):
     79                      bmrb_id = line[20:].strip()
     80                  elif line[2:].startswith('PDB ORIGIN'):
     81                      pdb_id = line[20:].strip()
     82                  elif line[2:].startswith('SEQUENCE PDB'):
     83                      sequence = line[20:].strip()
     84                      chain = line[17]
     85                  elif line[2:].startswith('PDB EXPTYPE'):
     86                      exptype = line[20:].strip()
     87              else:
     88                  break
     89
     90
     91          return ChemicalShiftContainer(bmrb_id, pdb_id, chain,
     92                                        sequence, exptype )
     93
     94
     95 -    def _parse_shifts(self, data, ignore_outliers=True):
     96
     97          while True:
     98              try:
     99                  line = next(self._stream)
    100              except StopIteration:
    101                  break
    102
    103              if ignore_outliers and "Shift outlier" in line:
    104                  continue
    105
    106              chain_id = line[7]
    107              res_code = line[9:14].strip()
    108              res_label = line[16:19].strip()
    109              res_ss = line[21]
    110              nucleus_name = line[23:28].strip()
    111              nucleus_element = line[41]
    112              shift = float(line[43:52])
    113
    114              info = ShiftInfo(res_code, res_label,
    115                               nucleus_name, shift,
    116                               nucleus_element, res_ss)
    117
    118              if not chain_id in data:
    119                  data.append(chain_id, csb.core.OrderedDict())
    120
    121              if not res_code in data[chain_id]:
    122                  data[chain_id][res_code] = {}
    123
    124
    125              data[chain_id][res_code][nucleus_name] = info
    126