def _build_logodata(options):
motif_flag = False
fin = options.fin
if options.upload is None:
if fin is None:
fin = StringIO(sys.stdin.read())
else:
if fin is None:
from . import _from_URL_fileopen
fin = _from_URL_fileopen(options.upload)
else:
raise ValueError(
"error: options --fin and --upload are incompatible")
try:
# Try reading data in transfac format first.
from corebio.matrix import Motif
motif = Motif.read_transfac(fin, alphabet=options.alphabet)
motif_flag = True
except ValueError as motif_err:
# Failed reading Motif, try reading as multiple sequence data.
if options.input_parser == "transfac":
raise motif_err # Adding transfac as str insted of parser is a bit of a ugly kludge
seqs = read_seq_data(fin,
options.input_parser.read,
alphabet=options.alphabet,
ignore_lower_case=options.ignore_lower_case)
if motif_flag:
if options.ignore_lower_case:
raise ValueError(
"error: option --ignore-lower-case incompatible with matrix input"
)
if options.reverse or options.revcomp:
motif.reverse()
if options.complement or options.revcomp:
motif.complement()
prior = parse_prior(options.composition, motif.alphabet,
options.weight)
data = LogoData.from_counts(motif.alphabet, motif, prior)
else:
if options.reverse or options.revcomp:
seqs = SeqList([s.reverse() for s in seqs], seqs.alphabet)
if options.complement or options.revcomp:
if not nucleic_alphabet.alphabetic(seqs.alphabet):
raise ValueError('non-nucleic sequence cannot be complemented')
aaa = seqs.alphabet
seqs.alphabet = nucleic_alphabet
seqs = SeqList([Seq(s, seqs.alphabet).complement() for s in seqs],
seqs.alphabet)
seqs.alphabet = aaa
prior = parse_prior(options.composition, seqs.alphabet, options.weight)
data = LogoData.from_seqs(seqs, prior)
return data
def complement(self):
"""Complement nucleic acid sequence."""
from corebio.seq import Seq, Alphabet
alphabet = self.alphabet
complement_alphabet = Alphabet(Seq(alphabet, alphabet).complement())
self.alphabets = (None, complement_alphabet)
m = self.reindex(alphabet)
self.alphabets = (None, alphabet)
self.array = m.array
def read(fin, alphabet=None):
""" Extract sequence data from a nexus file."""
n = Nexus(fin)
seqs = []
for taxon in n.taxlabels:
name = safename(taxon)
r = n.matrix[taxon]
if alphabet is None:
s = Seq(r, name=name, alphabet=r.alphabet)
else:
s = Seq(r, name=name, alphabet=alphabet)
seqs.append(s)
if len(seqs) == 0:
# Something went terrible wrong.
raise ValueError("Cannot parse file")
return SeqList(seqs)
def back_translate(self, seq):
"""Convert protein back into coding DNA.
Args:
-- seq - A polypeptide sequence.
Returns :
-- Seq - A DNA sequence
"""
# TODO: Optimzie
# TODO: Insanity check alphabet.
table = self.back_table
seq = str(seq)
trans = [table[a] for a in seq]
return Seq(''.join(trans), dna_alphabet)
def translate(self, seq, frame=0):
"""Translate a DNA sequence to a polypeptide using full
IUPAC ambiguities in DNA/RNA and amino acid codes.
Returns :
-- Seq - A polypeptide sequence
"""
# TODO: Optimize.
# TODO: Insanity check alphabet.
seq = str(seq)
table = self.table
trans = []
L = len(seq)
for i in range(frame, L - 2, 3):
codon = seq[i:i + 3].upper()
trans.append(table[codon])
return Seq(''.join(trans), protein_alphabet)
>>> from corebio.secstruc import *
>>> record = dssp.DsspRecord( open('test_corebio/data/1crn.dssp') )
>>> record.secondary()
' EE SSHHHHHHHHHHHTTT HHHHHHHHS EE SSS GGG '
>>> fa_reduce_secstruc_to_ehl(record.secondary())
'LEELLLHHHHHHHHHHHLLLLLHHHHHHHHLLEELLLLLLLLLLLL'
"""
__all__ = ['dssp', 'stride','secstruc_alphabet','secstruc_ehl_alphabet',
'fa_reduce_secstruc_to_ehl', 'ehl_reduce_secstruc_to_ehl']
from corebio.seq import Alphabet, Seq
from corebio.transform import Transform
# ------------------- SECONDARY STRUCTURE ALPHABETS -------------------
secstruc_alphabet = Alphabet("HGIEBbTSC _-L?X")
secstruc_ehl_alphabet = Alphabet("EHLX")
fa_reduce_secstruc_to_ehl = \
Transform( Seq("HGIEBbTSC _-L?X", secstruc_alphabet),
Seq("HLLELLLLLLLLLXX", secstruc_ehl_alphabet) )
ehl_reduce_secstruc_to_ehl = \
Transform( Seq("HGIEBbTSC _-L?X", secstruc_alphabet),
Seq("HHHEEELLLLLLLXX", secstruc_ehl_alphabet) )
def secondary(self):
"""Return the secondary structure of the protein as a Seq object"""
return Seq(''.join([r.secstruc for r in self.residues]),
stride_alphabet)
def primary(self):
""" Return the protein primary sequence as a Seq object."""
return Seq(''.join([r.aa for r in self.residues]), protein_alphabet)
ignore_lower_case = options.ignore_lower_case)
if motif_flag :
if options.ignore_lower_case:
raise ValueError("error: option --ignore-lower-case incompatible with matrix input")
if options.reverse: motif.reverse()
if options.complement: motif.complement()
prior = parse_prior( options.composition,motif.alphabet, options.weight)
data = LogoData.from_counts(motif.alphabet, motif, prior)
else :
if options.reverse:
seqs = SeqList([s.reverse() for s in seqs], seqs.alphabet)
if options.complement :
seqs= SeqList( [Seq(s,seqs.alphabet).complement() for s in seqs], seqs.alphabet)
prior = parse_prior( options.composition,seqs.alphabet, options.weight)
data = LogoData.from_seqs(seqs, prior)
return data
def _build_logoformat( logodata, opts) :
""" Extract and process relevant option values and return a
LogoFormat object."""
def iterseq(fin, alphabet=None) :
assert fin is not None
if alphabet is not None : pass
yield Seq('')
return
self.description = description
def __call__(self, seq):
"""Translate sequence."""
if not self.source.alphabet.alphabetic(seq):
raise ValueError("Incompatible alphabets")
s = str.translate(seq, self.table)
cls = self.target.__class__
return cls(s, self.target.alphabet, seq.name, seq.description)
# End class Translation
# FIXME: Test, document, add to seq.
dna_complement = Transform(
Seq("ACGTRYSWKMBDHVN-acgtUuryswkmbdhvnXx?.~", dna_alphabet),
Seq("TGCAYRSWMKVHDBN-tgcaAayrswmkvhdbnXx?.~", dna_alphabet),
)
def mask_low_complexity(seq, width=12, trigger=1.8, extension=2.0, mask='X'):
""" Mask low complexity regions in protein sequences.
Uses the method of Seg [1] by Wootton & Federhen [2] to divide a sequence
into regions of high and low complexity. The sequence is divided into
overlapping windows. Low complexity windows either have a sequence entropy
less than the trigger complexity, or have an entropy less than the extension
complexity and neighbor other low-complexity windows. The sequence within
a low complexity region is replaced with the mask character (default 'X'),
and the masked alphabetic sequence is returned.
