SMILES2PEPTIDE / app.py
yinuozhang's picture
bug fixing
6124ce7
raw
history blame
54.3 kB
import gradio as gr
import re
import pandas as pd
from io import StringIO
import rdkit
from rdkit import Chem
from rdkit.Chem import AllChem, Draw
import numpy as np
from PIL import Image, ImageDraw, ImageFont
import matplotlib.pyplot as plt
import matplotlib.patches as patches
from io import BytesIO
import tempfile
import re
import os
from rdkit import Chem
class PeptideAnalyzer:
def __init__(self):
self.bond_patterns = [
(r'OC\(=O\)', 'ester'), # Ester bond
(r'N\(C\)C\(=O\)', 'n_methyl'), # N-methylated peptide bond
(r'N[0-9]C\(=O\)', 'proline'), # Proline peptide bond
(r'NC\(=O\)', 'peptide'), # Standard peptide bond
(r'C\(=O\)N\(C\)', 'n_methyl_reverse'), # Reverse N-methylated
(r'C\(=O\)N[12]?', 'peptide_reverse') # Reverse peptide bond
]
# Three to one letter code mapping
self.three_to_one = {
'Ala': 'A', 'Cys': 'C', 'Asp': 'D', 'Glu': 'E',
'Phe': 'F', 'Gly': 'G', 'His': 'H', 'Ile': 'I',
'Lys': 'K', 'Leu': 'L', 'Met': 'M', 'Asn': 'N',
'Pro': 'P', 'Gln': 'Q', 'Arg': 'R', 'Ser': 'S',
'Thr': 'T', 'Val': 'V', 'Trp': 'W', 'Tyr': 'Y'
}
def is_peptide(self, smiles):
"""Check if the SMILES represents a peptide structure"""
mol = Chem.MolFromSmiles(smiles)
if mol is None:
return False
# Look for peptide bonds: NC(=O) pattern
peptide_bond_pattern = Chem.MolFromSmarts('[NH][C](=O)')
if mol.HasSubstructMatch(peptide_bond_pattern):
return True
# Look for N-methylated peptide bonds: N(C)C(=O) pattern
n_methyl_pattern = Chem.MolFromSmarts('[N;H0;$(NC)](C)[C](=O)')
if mol.HasSubstructMatch(n_methyl_pattern):
return True
return False
def is_cyclic(self, smiles):
"""Improved cyclic peptide detection"""
# Check for C-terminal carboxyl
if smiles.endswith('C(=O)O'):
return False, [], []
# Find all numbers used in ring closures
ring_numbers = re.findall(r'(?:^|[^c])[0-9](?=[A-Z@\(\)])', smiles)
# Find aromatic ring numbers
aromatic_matches = re.findall(r'c[0-9](?:ccccc|c\[nH\]c)[0-9]', smiles)
aromatic_cycles = []
for match in aromatic_matches:
numbers = re.findall(r'[0-9]', match)
aromatic_cycles.extend(numbers)
# Numbers that aren't part of aromatic rings are peptide cycles
peptide_cycles = [n for n in ring_numbers if n not in aromatic_cycles]
is_cyclic = len(peptide_cycles) > 0 and not smiles.endswith('C(=O)O')
return is_cyclic, peptide_cycles, aromatic_cycles
def split_on_bonds(self, smiles):
"""Split SMILES into segments with simplified Pro handling"""
positions = []
used = set()
# Find Gly pattern first
gly_pattern = r'NCC\(=O\)'
for match in re.finditer(gly_pattern, smiles):
if not any(p in range(match.start(), match.end()) for p in used):
positions.append({
'start': match.start(),
'end': match.end(),
'type': 'gly',
'pattern': match.group()
})
used.update(range(match.start(), match.end()))
for pattern, bond_type in self.bond_patterns:
for match in re.finditer(pattern, smiles):
if not any(p in range(match.start(), match.end()) for p in used):
positions.append({
'start': match.start(),
'end': match.end(),
'type': bond_type,
'pattern': match.group()
})
used.update(range(match.start(), match.end()))
# Sort by position
positions.sort(key=lambda x: x['start'])
# Create segments
segments = []
if positions:
# First segment
if positions[0]['start'] > 0:
segments.append({
'content': smiles[0:positions[0]['start']],
'bond_after': positions[0]['pattern']
})
# Process segments
for i in range(len(positions)-1):
current = positions[i]
next_pos = positions[i+1]
if current['type'] == 'gly':
segments.append({
'content': 'NCC(=O)',
'bond_before': positions[i-1]['pattern'] if i > 0 else None,
'bond_after': next_pos['pattern']
})
else:
content = smiles[current['end']:next_pos['start']]
if content:
segments.append({
'content': content,
'bond_before': current['pattern'],
'bond_after': next_pos['pattern']
})
# Last segment
if positions[-1]['end'] < len(smiles):
segments.append({
'content': smiles[positions[-1]['end']:],
'bond_before': positions[-1]['pattern']
})
return segments
def clean_terminal_carboxyl(self, segment):
"""Remove C-terminal carboxyl only if it's the true terminus"""
content = segment['content']
# Only clean if:
# 1. Contains C(=O)O
# 2. No bond_after exists (meaning it's the last segment)
# 3. C(=O)O is at the end of the content
if 'C(=O)O' in content and not segment.get('bond_after'):
print('recognized?')
# Remove C(=O)O pattern regardless of position
cleaned = re.sub(r'\(C\(=O\)O\)', '', content)
# Remove any leftover empty parentheses
cleaned = re.sub(r'\(\)', '', cleaned)
print(cleaned)
return cleaned
return content
def identify_residue(self, segment):
"""Identify residue with Pro reconstruction"""
# Only clean terminal carboxyl if this is the last segment
content = self.clean_terminal_carboxyl(segment)
mods = self.get_modifications(segment)
# UAA pattern matching section - before regular residues
# Phenylglycine and derivatives
if 'c1ccccc1' in content:
if '[C@@H](c1ccccc1)' in content or '[C@H](c1ccccc1)' in content:
return '4', mods # Base phenylglycine
# 4-substituted phenylalanines
if 'Cc1ccc' in content:
if 'OMe' in content or 'OCc1ccc' in content:
return '0A1', mods # 4-methoxy-Phenylalanine
elif 'Clc1ccc' in content:
return '200', mods # 4-chloro-Phenylalanine
elif 'Brc1ccc' in content:
return '4BF', mods # 4-Bromo-phenylalanine
elif 'C#Nc1ccc' in content:
return '4CF', mods # 4-cyano-phenylalanine
elif 'Ic1ccc' in content:
return 'PHI', mods # 4-Iodo-phenylalanine
elif 'Fc1ccc' in content:
return 'PFF', mods # 4-Fluoro-phenylalanine
# Modified tryptophans
if 'c[nH]c2' in content:
if 'Oc2cccc2' in content:
return '0AF', mods # 7-hydroxy-tryptophan
elif 'Fc2cccc2' in content:
return '4FW', mods # 4-fluoro-tryptophan
elif 'Clc2cccc2' in content:
return '6CW', mods # 6-chloro-tryptophan
elif 'Brc2cccc2' in content:
return 'BTR', mods # 6-bromo-tryptophan
elif 'COc2cccc2' in content:
return 'MOT5', mods # 5-Methoxy-tryptophan
elif 'Cc2cccc2' in content:
return 'MTR5', mods # 5-Methyl-tryptophan
# Special amino acids
if 'CC(C)(C)[C@@H]' in content or 'CC(C)(C)[C@H]' in content:
return 'BUG', mods # Tertleucine
if 'CCCNC(=N)N' in content:
return 'CIR', mods # Citrulline
if '[SeH]' in content:
return 'CSE', mods # Selenocysteine
if '[NH3]CC[C@@H]' in content or '[NH3]CC[C@H]' in content:
return 'DAB', mods # Diaminobutyric acid
if 'C1CCCCC1' in content:
if 'C1CCCCC1[C@@H]' in content or 'C1CCCCC1[C@H]' in content:
return 'CHG', mods # Cyclohexylglycine
elif 'C1CCCCC1C[C@@H]' in content or 'C1CCCCC1C[C@H]' in content:
return 'ALC', mods # 3-cyclohexyl-alanine
# Naphthalene derivatives
if 'c1cccc2c1cccc2' in content:
if 'c1cccc2c1cccc2[C@@H]' in content or 'c1cccc2c1cccc2[C@H]' in content:
return 'NAL', mods # 2-Naphthyl-alanine
# Heteroaromatic derivatives
if 'c1cncc' in content:
return 'PYR4', mods # 3-(4-Pyridyl)-alanine
if 'c1cscc' in content:
return 'THA3', mods # 3-(3-thienyl)-alanine
if 'c1nnc' in content:
return 'TRZ4', mods # 3-(1,2,4-Triazol-1-yl)-alanine
# Modified serines and threonines
if 'OP(O)(O)O' in content:
if '[C@@H](COP' in content or '[C@H](COP' in content:
return 'SEP', mods # phosphoserine
elif '[C@@H](OP' in content or '[C@H](OP' in content:
return 'TPO', mods # phosphothreonine
# Specialized ring systems
if 'c1c2ccccc2cc2c1cccc2' in content:
return 'ANTH', mods # 3-(9-anthryl)-alanine
if 'c1csc2c1cccc2' in content:
return 'BTH3', mods # 3-(3-benzothienyl)-alanine
if '[C@]12C[C@H]3C[C@@H](C2)C[C@@H](C1)C3' in content:
return 'ADAM', mods # Adamanthane
# Fluorinated derivatives
if 'FC(F)(F)' in content:
if 'CC(F)(F)F' in content:
return 'FLA', mods # Trifluoro-alanine
if 'C(F)(F)F)c1' in content:
if 'c1ccccc1C(F)(F)F' in content:
return 'TFG2', mods # 2-(Trifluoromethyl)-phenylglycine
if 'c1cccc(c1)C(F)(F)F' in content:
return 'TFG3', mods # 3-(Trifluoromethyl)-phenylglycine
if 'c1ccc(cc1)C(F)(F)F' in content:
return 'TFG4', mods # 4-(Trifluoromethyl)-phenylglycine
# Multiple halogen patterns
if 'F' in content and 'c1' in content:
if 'c1ccc(c(c1)F)F' in content:
return 'F2F', mods # 3,4-Difluoro-phenylalanine
if 'cc(F)cc(c1)F' in content:
return 'WFP', mods # 3,5-Difluoro-phenylalanine
if 'Cl' in content and 'c1' in content:
if 'c1ccc(cc1Cl)Cl' in content:
return 'CP24', mods # 2,4-dichloro-phenylalanine
if 'c1ccc(c(c1)Cl)Cl' in content:
return 'CP34', mods # 3,4-dichloro-phenylalanine
# Hydroxy and amino derivatives
if 'O' in content and 'c1' in content:
if 'c1cc(O)cc(c1)O' in content:
return '3FG', mods # (2s)-amino(3,5-dihydroxyphenyl)-ethanoic acid
if 'c1ccc(c(c1)O)O' in content:
return 'DAH', mods # 3,4-Dihydroxy-phenylalanine
# Cyclic amino acids
if 'C1CCCC1' in content:
return 'CPA3', mods # 3-Cyclopentyl-alanine
if 'C1CCCCC1' in content:
if 'CC1CCCCC1' in content:
return 'ALC', mods # 3-cyclohexyl-alanine
else:
return 'CHG', mods # Cyclohexylglycine
# Chain-length variants
if 'CCC[C@@H]' in content or 'CCC[C@H]' in content:
return 'NLE', mods # Norleucine
if 'CC[C@@H]' in content or 'CC[C@H]' in content:
if not any(x in content for x in ['CC(C)', 'COC', 'CN(']):
return 'ABA', mods # 2-Aminobutyric acid
# Modified histidines
if 'c1cnc' in content:
if '[C@@H]1CN[C@@H](N1)F' in content:
return '2HF', mods # 2-fluoro-l-histidine
if 'c1cnc([nH]1)F' in content:
return '2HF1', mods # 2-fluoro-l-histidine variant
if 'c1c[nH]c(n1)F' in content:
return '2HF2', mods # 2-fluoro-l-histidine variant
# Sulfur and selenium containing
if '[SeH]' in content:
return 'CSE', mods # Selenocysteine
if 'S' in content:
if 'CSCc1ccccc1' in content:
return 'BCS', mods # benzylcysteine
if 'CCSC' in content:
return 'ESC', mods # Ethionine
if 'CCS' in content:
return 'HCS', mods # homocysteine
# Additional modifications
if 'CN=[N]=N' in content:
return 'AZDA', mods # azido-alanine
if '[NH]=[C](=[NH2])=[NH2]' in content:
if 'CCC[NH]=' in content:
return 'AGM', mods # 5-methyl-arginine
if 'CC[NH]=' in content:
return 'GDPR', mods # 2-Amino-3-guanidinopropionic acid
if 'CCON' in content:
return 'CAN', mods # canaline
if '[C@@H]1C=C[C@@H](C=C1)' in content:
return 'ACZ', mods # cis-amiclenomycin
if 'CCC(=O)[NH3]' in content:
return 'ONL', mods # 5-oxo-l-norleucine
if 'c1ccncc1' in content:
return 'PYR4', mods # 3-(4-Pyridyl)-alanine
if 'c1ccco1' in content:
return 'FUA2', mods # (2-furyl)-alanine
if 'c1ccc' in content:
if 'c1ccc(cc1)c1ccccc1' in content:
return 'BIF', mods # 4,4-biphenylalanine
if 'c1ccc(cc1)C(=O)c1ccccc1' in content:
return 'PBF', mods # 4-benzoyl-phenylalanine
if 'c1ccc(cc1)C(C)(C)C' in content:
return 'TBP4', mods # 4-tert-butyl-phenylalanine
if 'c1ccc(cc1)[C](=[NH2])=[NH2]' in content:
return '0BN', mods # 4-carbamimidoyl-l-phenylalanine
if 'c1cccc(c1)[C](=[NH2])=[NH2]' in content:
return 'APM', mods # m-amidinophenyl-3-alanine
# Multiple hydroxy patterns
if 'O' in content:
if '[C@H]([C@H](C)O)O' in content:
return 'ILX', mods # 4,5-dihydroxy-isoleucine
if '[C@H]([C@@H](C)O)O' in content:
return 'ALO', mods # Allo-threonine
if '[C@H](COP(O)(O)O)' in content:
return 'SEP', mods # phosphoserine
if '[C@H]([C@@H](C)OP(O)(O)O)' in content:
return 'TPO', mods # phosphothreonine
if '[C@H](c1ccc(O)cc1)O' in content:
return 'OMX', mods # (betar)-beta-hydroxy-l-tyrosine
if '[C@H](c1ccc(c(Cl)c1)O)O' in content:
return 'OMY', mods # (betar)-3-chloro-beta-hydroxy-l-tyrosine
# Heterocyclic patterns
if 'n1' in content:
if 'n1cccn1' in content:
return 'PYZ1', mods # 3-(1-Pyrazolyl)-alanine
if 'n1nncn1' in content:
return 'TEZA', mods # 3-(2-Tetrazolyl)-alanine
if 'c2c(n1)cccc2' in content:
return 'QU32', mods # 3-(2-Quinolyl)-alanine
if 'c1cnc2c(c1)cccc2' in content:
return 'QU33', mods # 3-(3-quinolyl)-alanine
if 'c1ccnc2c1cccc2' in content:
return 'QU34', mods # 3-(4-quinolyl)-alanine
if 'c1ccc2c(c1)nccc2' in content:
return 'QU35', mods # 3-(5-Quinolyl)-alanine
if 'c1ccc2c(c1)cncc2' in content:
return 'QU36', mods # 3-(6-Quinolyl)-alanine
if 'c1cnc2c(n1)cccc2' in content:
return 'QX32', mods # 3-(2-quinoxalyl)-alanine
# Multiple nitrogen patterns
if 'N' in content:
if '[NH3]CC[C@@H]' in content:
return 'DAB', mods # Diaminobutyric acid
if '[NH3]C[C@@H]' in content:
return 'DPP', mods # 2,3-Diaminopropanoic acid
if '[NH3]CCCCCC[C@@H]' in content:
return 'HHK', mods # (2s)-2,8-diaminooctanoic acid
if 'CCC[NH]=[C](=[NH2])=[NH2]' in content:
return 'GBUT', mods # 2-Amino-4-guanidinobutryric acid
if '[NH]=[C](=S)=[NH2]' in content:
return 'THIC', mods # Thio-citrulline
# Chain modified amino acids
if 'CC' in content:
if 'CCCC[C@@H]' in content:
return 'AHP', mods # 2-Aminoheptanoic acid
if 'CCC([C@@H])(C)C' in content:
return 'I2M', mods # 3-methyl-l-alloisoleucine
if 'CC[C@H]([C@@H])C' in content:
return 'IIL', mods # Allo-Isoleucine
if '[C@H](CCC(C)C)' in content:
return 'HLEU', mods # Homoleucine
if '[C@@H]([C@@H](C)O)C' in content:
return 'HLU', mods # beta-hydroxyleucine
# Modified glutamate/aspartate patterns
if '[C@@H]' in content:
if '[C@@H](C[C@@H](F))' in content:
return 'FGA4', mods # 4-Fluoro-glutamic acid
if '[C@@H](C[C@@H](O))' in content:
return '3GL', mods # 4-hydroxy-glutamic-acid
if '[C@@H](C[C@H](C))' in content:
return 'LME', mods # (3r)-3-methyl-l-glutamic acid
if '[C@@H](CC[C@H](C))' in content:
return 'MEG', mods # (3s)-3-methyl-l-glutamic acid
# Sulfur and selenium modifications
if 'S' in content:
if 'SCC[C@@H]' in content:
return 'HSER', mods # homoserine
if 'SCCN' in content:
return 'SLZ', mods # thialysine
if 'SC(=O)' in content:
return 'CSA', mods # s-acetonylcysteine
if '[S@@](=O)' in content:
return 'SME', mods # Methionine sulfoxide
if 'S(=O)(=O)' in content:
return 'OMT', mods # Methionine sulfone
# Double bond containing
if 'C=' in content:
if 'C=C[C@@H]' in content:
return '2AG', mods # 2-Allyl-glycine
if 'C=C[C@@H]' in content:
return 'LVG', mods # vinylglycine
if 'C=Cc1ccccc1' in content:
return 'STYA', mods # Styrylalanine
# Special cases
if '[C@@H]1Cc2c(C1)cccc2' in content:
return 'IGL', mods # alpha-amino-2-indanacetic acid
if '[C](=[C](=O)=O)=O' in content:
return '26P', mods # 2-amino-6-oxopimelic acid
if '[C](=[C](=O)=O)=C' in content:
return '2NP', mods # l-2-amino-6-methylene-pimelic acid
if 'c2cnc[nH]2' in content:
return 'HIS', mods # histidine core
if 'c1cccc2c1cc(O)cc2' in content:
return 'NAO1', mods # 5-hydroxy-1-naphthalene
if 'c1ccc2c(c1)cc(O)cc2' in content:
return 'NAO2', mods # 6-hydroxy-2-naphthalene
# Proline (P) - flexible ring numbers
if any([
# Check for any ring number in bond patterns
(segment.get('bond_after', '').startswith(f'N{n}C(=O)') and 'CCC' in content and
any(f'[C@@H]{n}' in content or f'[C@H]{n}' in content for n in '123456789'))
for n in '123456789'
]) or any([
# Check ending patterns with any ring number
(f'CCCN{n}' in content and content.endswith('=O') and
any(f'[C@@H]{n}' in content or f'[C@H]{n}' in content for n in '123456789'))
for n in '123456789'
]) or any([
# Handle CCC[C@H]n patterns
(content == f'CCC[C@H]{n}' and segment.get('bond_before', '').startswith(f'C(=O)N{n}')) or
(content == f'CCC[C@@H]{n}' and segment.get('bond_before', '').startswith(f'C(=O)N{n}')) or
# N-terminal Pro with any ring number
(f'N{n}CCC[C@H]{n}' in content) or
(f'N{n}CCC[C@@H]{n}' in content)
for n in '123456789'
]):
return 'Pro', mods
# Tryptophan (W) - more specific indole pattern
if re.search(r'c[0-9]c\[nH\]c[0-9]ccccc[0-9][0-9]', content) and \
'c[nH]c' in content.replace(' ', ''):
return 'Trp', mods
# Lysine (K) - both patterns
if '[C@@H](CCCCN)' in content or '[C@H](CCCCN)' in content:
return 'Lys', mods
# Arginine (R) - both patterns
if '[C@@H](CCCNC(=N)N)' in content or '[C@H](CCCNC(=N)N)' in content:
return 'Arg', mods
if ('C[C@H](CCCC)' in content or 'C[C@@H](CCCC)' in content) and 'CC(C)' not in content:
return 'Nle', mods
# Ornithine (Orn) - 3-carbon chain with NH2
if ('C[C@H](CCCN)' in content or 'C[C@@H](CCCN)' in content) and 'CC(C)' not in content:
return 'Orn', mods
# 2-Naphthylalanine (2Nal) - distinct from Phe pattern
if ('Cc3cc2ccccc2c3' in content) and ('C[C@H]' in content or 'C[C@@H]' in content):
return '2Nal', mods
# Cyclohexylalanine (Cha) - already in your code but moved here for clarity
if 'N2CCCCC2' in content or 'CCCCC2' in content:
return 'Cha', mods
# Aminobutyric acid (Abu) - 2-carbon chain
if ('C[C@H](CC)' in content or 'C[C@@H](CC)' in content) and not any(p in content for p in ['CC(C)', 'CCCC', 'CCC(C)']):
return 'Abu', mods
# Pipecolic acid (Pip) - 6-membered ring like Pro
if ('N3CCCCC3' in content or 'CCCCC3' in content) and ('C[C@H]' in content or 'C[C@@H]' in content):
return 'Pip', mods
# Cyclohexylglycine (Chg) - direct cyclohexyl without CH2
if ('C[C@H](C1CCCCC1)' in content or 'C[C@@H](C1CCCCC1)' in content):
return 'Chg', mods
# 4-Fluorophenylalanine (4F-Phe)
if ('Cc2ccc(F)cc2' in content) and ('C[C@H]' in content or 'C[C@@H]' in content):
return '4F-Phe', mods
# Regular residue identification
if ('NCC(=O)' in content) or (content == 'C'):
# Middle case - between bonds
if segment.get('bond_before') and segment.get('bond_after'):
if ('C(=O)N' in segment['bond_before'] or 'C(=O)N(C)' in segment['bond_before']):
return 'Gly', mods
# Terminal case - at the end
elif segment.get('bond_before') and segment.get('bond_before').startswith('C(=O)N'):
return 'Gly', mods
if 'CC(C)C[C@H]' in content or 'CC(C)C[C@@H]' in content:
return 'Leu', mods
if '[C@@H](CC(C)C)' in content or '[C@H](CC(C)C)' in content:
return 'Leu', mods
if '[C@@H]([C@@H](C)O)' in content or '[C@H]([C@H](C)O)' in content:
return 'Thr', mods
if '[C@H](Cc2ccccc2)' in content or '[C@@H](Cc2ccccc2)' in content:
return 'Phe', mods
if ('[C@H](C(C)C)' in content or # With outer parentheses
'[C@@H](C(C)C)' in content or # With outer parentheses
'[C@H]C(C)C' in content or # Without outer parentheses
'[C@@H]C(C)C' in content): # Without outer parentheses
if not any(p in content for p in ['CC(C)C[C@H]', 'CC(C)C[C@@H]']): # Still check not Leu
return 'Val', mods
if '[C@H](COC(C)(C)C)' in content or '[C@@H](COC(C)(C)C)' in content:
return 'O-tBu', mods
if any([
'CC[C@H](C)' in content,
'CC[C@@H](C)' in content,
'C(C)C[C@H]' in content and 'CC(C)C' not in content,
'C(C)C[C@@H]' in content and 'CC(C)C' not in content
]):
return 'Ile', mods
if ('[C@H](C)' in content or '[C@@H](C)' in content):
if not any(p in content for p in ['C(C)C', 'COC', 'CN(', 'C(C)O', 'CC[C@H]', 'CC[C@@H]']):
return 'Ala', mods
# Tyrosine (Tyr) - 4-hydroxybenzyl side chain
if re.search(r'Cc[0-9]ccc\(O\)cc[0-9]', content):
return 'Tyr', mods
# Serine (Ser) - Hydroxymethyl side chain
if '[C@H](CO)' in content or '[C@@H](CO)' in content:
if not ('C(C)O' in content or 'COC' in content):
return 'Ser', mods
# Threonine (Thr) - 1-hydroxyethyl side chain
if '[C@@H]([C@@H](C)O)' in content or '[C@H]([C@H](C)O)' in content or '[C@@H](C)O' in content or '[C@H](C)O' in content:
return 'Thr', mods
# Cysteine (Cys) - Thiol side chain
if '[C@H](CS)' in content or '[C@@H](CS)' in content:
return 'Cys', mods
# Methionine (Met) - Methylthioethyl side chain
if ('C[C@H](CCSC)' in content or 'C[C@@H](CCSC)' in content):
return 'Met', mods
# Asparagine (Asn) - Carbamoylmethyl side chain
if ('CC(=O)N' in content) and ('C[C@H]' in content or 'C[C@@H]' in content):
return 'Asn', mods
# Glutamine (Gln) - Carbamoylethyl side chain
if ('CCC(=O)N' in content) and ('C[C@H]' in content or 'C[C@@H]' in content):
return 'Gln', mods
# Aspartic acid (Asp) - Carboxymethyl side chain
if ('CC(=O)O' in content) and ('C[C@H]' in content or 'C[C@@H]' in content):
return 'Asp', mods
# Glutamic acid (Glu) - Carboxyethyl side chain
if ('CCC(=O)O' in content) and ('C[C@H]' in content or 'C[C@@H]' in content):
return 'Glu', mods
# Arginine (Arg) - 3-guanidinopropyl side chain
if ('CCCNC(=N)N' in content) and ('C[C@H]' in content or 'C[C@@H]' in content):
return 'Arg', mods
# Histidine (His) - Imidazole side chain
if ('Cc2cnc[nH]2' in content) and ('C[C@H]' in content or 'C[C@@H]' in content):
return 'His', mods
return None, mods
def get_modifications(self, segment):
"""Get modifications based on bond types"""
mods = []
if segment.get('bond_after'):
if 'N(C)' in segment['bond_after'] or segment['bond_after'].startswith('C(=O)N(C)'):
mods.append('N-Me')
if 'OC(=O)' in segment['bond_after']:
mods.append('O-linked')
return mods
def analyze_structure(self, smiles):
"""Main analysis function with debug output"""
print("\nAnalyzing structure:", smiles)
# Split into segments
segments = self.split_on_bonds(smiles)
print("\nSegment Analysis:")
sequence = []
for i, segment in enumerate(segments):
print(f"\nSegment {i}:")
print(f"Content: {segment['content']}")
print(f"Bond before: {segment.get('bond_before', 'None')}")
print(f"Bond after: {segment.get('bond_after', 'None')}")
residue, mods = self.identify_residue(segment)
if residue:
if mods:
sequence.append(f"{residue}({','.join(mods)})")
else:
sequence.append(residue)
print(f"Identified as: {residue}")
print(f"Modifications: {mods}")
else:
print(f"Warning: Could not identify residue in segment: {segment['content']}")
# Check if cyclic
is_cyclic, peptide_cycles, aromatic_cycles = self.is_cyclic(smiles)
three_letter = '-'.join(sequence)
one_letter = ''.join(self.three_to_one.get(aa.split('(')[0], 'X') for aa in sequence)
if is_cyclic:
three_letter = f"cyclo({three_letter})"
one_letter = f"cyclo({one_letter})"
print(f"\nFinal sequence: {three_letter}")
print(f"One-letter code: {one_letter}")
print(f"Is cyclic: {is_cyclic}")
#print(f"Peptide cycles: {peptide_cycles}")
#print(f"Aromatic cycles: {aromatic_cycles}")
return {
'three_letter': three_letter,
'one_letter': one_letter,
'is_cyclic': is_cyclic
}
"""
def annotate_cyclic_structure(mol, sequence):
'''Create annotated 2D structure with clear, non-overlapping residue labels'''
# Generate 2D coordinates
# Generate 2D coordinates
AllChem.Compute2DCoords(mol)
# Create drawer with larger size for annotations
drawer = Draw.rdMolDraw2D.MolDraw2DCairo(2000, 2000) # Even larger size
# Get residue list and reverse it to match structural representation
if sequence.startswith('cyclo('):
residues = sequence[6:-1].split('-')
else:
residues = sequence.split('-')
residues = list(reversed(residues)) # Reverse the sequence
# Draw molecule first to get its bounds
drawer.drawOptions().addAtomIndices = False
drawer.DrawMolecule(mol)
drawer.FinishDrawing()
# Convert to PIL Image
img = Image.open(BytesIO(drawer.GetDrawingText()))
draw = ImageDraw.Draw(img)
try:
# Try to use DejaVuSans as it's commonly available on Linux systems
font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", 60)
small_font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", 60)
except OSError:
try:
# Fallback to Arial if available (common on Windows)
font = ImageFont.truetype("arial.ttf", 60)
small_font = ImageFont.truetype("arial.ttf", 60)
except OSError:
# If no TrueType fonts are available, fall back to default
print("Warning: TrueType fonts not available, using default font")
font = ImageFont.load_default()
small_font = ImageFont.load_default()
# Get molecule bounds
conf = mol.GetConformer()
positions = []
for i in range(mol.GetNumAtoms()):
pos = conf.GetAtomPosition(i)
positions.append((pos.x, pos.y))
x_coords = [p[0] for p in positions]
y_coords = [p[1] for p in positions]
min_x, max_x = min(x_coords), max(x_coords)
min_y, max_y = min(y_coords), max(y_coords)
# Calculate scaling factors
scale = 150 # Increased scale factor
center_x = 1000 # Image center
center_y = 1000
# Add residue labels in a circular arrangement around the structure
n_residues = len(residues)
radius = 700 # Distance of labels from center
# Start from the rightmost point (3 o'clock position) and go counterclockwise
# Offset by -3 positions to align with structure
offset = 0 # Adjust this value to match the structure alignment
for i, residue in enumerate(residues):
# Calculate position in a circle around the structure
# Start from 0 (3 o'clock) and go counterclockwise
angle = -(2 * np.pi * ((i + offset) % n_residues) / n_residues)
# Calculate label position
label_x = center_x + radius * np.cos(angle)
label_y = center_y + radius * np.sin(angle)
# Draw residue label
text = f"{i+1}. {residue}"
bbox = draw.textbbox((label_x, label_y), text, font=font)
padding = 10
draw.rectangle([bbox[0]-padding, bbox[1]-padding,
bbox[2]+padding, bbox[3]+padding],
fill='white', outline='white')
draw.text((label_x, label_y), text,
font=font, fill='black', anchor="mm")
# Add sequence at the top with white background
seq_text = f"Sequence: {sequence}"
bbox = draw.textbbox((center_x, 100), seq_text, font=small_font)
padding = 10
draw.rectangle([bbox[0]-padding, bbox[1]-padding,
bbox[2]+padding, bbox[3]+padding],
fill='white', outline='white')
draw.text((center_x, 100), seq_text,
font=small_font, fill='black', anchor="mm")
return img
"""
def annotate_cyclic_structure(mol, sequence):
"""Create structure visualization with just the sequence header"""
# Generate 2D coordinates
AllChem.Compute2DCoords(mol)
# Create drawer with larger size for annotations
drawer = Draw.rdMolDraw2D.MolDraw2DCairo(2000, 2000)
# Draw molecule first
drawer.drawOptions().addAtomIndices = False
drawer.DrawMolecule(mol)
drawer.FinishDrawing()
# Convert to PIL Image
img = Image.open(BytesIO(drawer.GetDrawingText()))
draw = ImageDraw.Draw(img)
try:
small_font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", 60)
except OSError:
try:
small_font = ImageFont.truetype("arial.ttf", 60)
except OSError:
print("Warning: TrueType fonts not available, using default font")
small_font = ImageFont.load_default()
# Add just the sequence header at the top
seq_text = f"Sequence: {sequence}"
bbox = draw.textbbox((1000, 100), seq_text, font=small_font)
padding = 10
draw.rectangle([bbox[0]-padding, bbox[1]-padding,
bbox[2]+padding, bbox[3]+padding],
fill='white', outline='white')
draw.text((1000, 100), seq_text,
font=small_font, fill='black', anchor="mm")
return img
def create_enhanced_linear_viz(sequence, smiles):
"""Create an enhanced linear representation using PeptideAnalyzer"""
analyzer = PeptideAnalyzer() # Create analyzer instance
# Create figure with two subplots
fig = plt.figure(figsize=(15, 10))
gs = fig.add_gridspec(2, 1, height_ratios=[1, 2])
ax_struct = fig.add_subplot(gs[0])
ax_detail = fig.add_subplot(gs[1])
# Parse sequence and get residues
if sequence.startswith('cyclo('):
residues = sequence[6:-1].split('-')
else:
residues = sequence.split('-')
# Get segments using analyzer
segments = analyzer.split_on_bonds(smiles)
# Debug print
print(f"Number of residues: {len(residues)}")
print(f"Number of segments: {len(segments)}")
# Top subplot - Basic structure
ax_struct.set_xlim(0, 10)
ax_struct.set_ylim(0, 2)
num_residues = len(residues)
spacing = 9.0 / (num_residues - 1) if num_residues > 1 else 9.0
# Draw basic structure
y_pos = 1.5
for i in range(num_residues):
x_pos = 0.5 + i * spacing
# Draw amino acid box
rect = patches.Rectangle((x_pos-0.3, y_pos-0.2), 0.6, 0.4,
facecolor='lightblue', edgecolor='black')
ax_struct.add_patch(rect)
# Draw connecting bonds if not the last residue
if i < num_residues - 1:
segment = segments[i] if i < len(segments) else None
if segment:
# Determine bond type from segment info
bond_type = 'ester' if 'O-linked' in segment.get('bond_after', '') else 'peptide'
is_n_methylated = 'N-Me' in segment.get('bond_after', '')
bond_color = 'red' if bond_type == 'ester' else 'black'
linestyle = '--' if bond_type == 'ester' else '-'
# Draw bond line
ax_struct.plot([x_pos+0.3, x_pos+spacing-0.3], [y_pos, y_pos],
color=bond_color, linestyle=linestyle, linewidth=2)
# Add bond type label
mid_x = x_pos + spacing/2
bond_label = f"{bond_type}"
if is_n_methylated:
bond_label += "\n(N-Me)"
ax_struct.text(mid_x, y_pos+0.1, bond_label,
ha='center', va='bottom', fontsize=10,
color=bond_color)
# Add residue label
ax_struct.text(x_pos, y_pos-0.5, residues[i],
ha='center', va='top', fontsize=14)
# Bottom subplot - Detailed breakdown
ax_detail.set_ylim(0, len(segments)+1)
ax_detail.set_xlim(0, 1)
# Create detailed breakdown
segment_y = len(segments) # Start from top
for i, segment in enumerate(segments):
y = segment_y - i
# Check if this is a bond or residue
residue, mods = analyzer.identify_residue(segment)
if residue:
text = f"Residue {i+1}: {residue}"
if mods:
text += f" ({', '.join(mods)})"
color = 'blue'
else:
# Must be a bond
text = f"Bond {i}: "
if 'O-linked' in segment.get('bond_after', ''):
text += "ester"
elif 'N-Me' in segment.get('bond_after', ''):
text += "peptide (N-methylated)"
else:
text += "peptide"
color = 'red'
# Add segment analysis
ax_detail.text(0.05, y, text, fontsize=12, color=color)
ax_detail.text(0.5, y, f"SMILES: {segment.get('content', '')}", fontsize=10, color='gray')
# If cyclic, add connection indicator
if sequence.startswith('cyclo('):
ax_struct.annotate('', xy=(9.5, y_pos), xytext=(0.5, y_pos),
arrowprops=dict(arrowstyle='<->', color='red', lw=2))
ax_struct.text(5, y_pos+0.3, 'Cyclic Connection',
ha='center', color='red', fontsize=14)
# Add titles and adjust layout
ax_struct.set_title("Peptide Structure Overview", pad=20)
ax_detail.set_title("Segment Analysis Breakdown", pad=20)
# Remove axes
for ax in [ax_struct, ax_detail]:
ax.set_xticks([])
ax.set_yticks([])
ax.axis('off')
plt.tight_layout()
return fig
class PeptideStructureGenerator:
"""A class to generate 3D structures of peptides using different embedding methods"""
@staticmethod
def prepare_molecule(smiles):
"""Prepare molecule with proper hydrogen handling"""
mol = Chem.MolFromSmiles(smiles, sanitize=False)
if mol is None:
raise ValueError("Failed to create molecule from SMILES")
# Calculate valence for each atom
for atom in mol.GetAtoms():
atom.UpdatePropertyCache(strict=False)
# Sanitize with reduced requirements
Chem.SanitizeMol(mol,
sanitizeOps=Chem.SANITIZE_FINDRADICALS|
Chem.SANITIZE_KEKULIZE|
Chem.SANITIZE_SETAROMATICITY|
Chem.SANITIZE_SETCONJUGATION|
Chem.SANITIZE_SETHYBRIDIZATION|
Chem.SANITIZE_CLEANUPCHIRALITY)
mol = Chem.AddHs(mol)
return mol
@staticmethod
def get_etkdg_params(attempt=0):
"""Get ETKDG parameters with optional modifications based on attempt number"""
params = AllChem.ETKDGv3()
params.randomSeed = -1
params.maxIterations = 200
params.numThreads = 4 # Reduced for web interface
params.useBasicKnowledge = True
params.enforceChirality = True
params.useExpTorsionAnglePrefs = True
params.useSmallRingTorsions = True
params.useMacrocycleTorsions = True
params.ETversion = 2
params.pruneRmsThresh = -1
params.embedRmsThresh = 0.5
if attempt > 10:
params.bondLength = 1.5 + (attempt - 10) * 0.02
params.useExpTorsionAnglePrefs = False
return params
def generate_structure_etkdg(self, smiles, max_attempts=20):
"""Generate 3D structure using ETKDG without UFF optimization"""
success = False
mol = None
for attempt in range(max_attempts):
try:
mol = self.prepare_molecule(smiles)
params = self.get_etkdg_params(attempt)
if AllChem.EmbedMolecule(mol, params) == 0:
success = True
break
except Exception as e:
continue
if not success:
raise ValueError("Failed to generate structure with ETKDG")
return mol
def generate_structure_uff(self, smiles, max_attempts=20):
"""Generate 3D structure using ETKDG followed by UFF optimization"""
best_mol = None
lowest_energy = float('inf')
for attempt in range(max_attempts):
try:
test_mol = self.prepare_molecule(smiles)
params = self.get_etkdg_params(attempt)
if AllChem.EmbedMolecule(test_mol, params) == 0:
res = AllChem.UFFOptimizeMolecule(test_mol, maxIters=2000,
vdwThresh=10.0, confId=0,
ignoreInterfragInteractions=True)
if res == 0:
ff = AllChem.UFFGetMoleculeForceField(test_mol)
if ff:
current_energy = ff.CalcEnergy()
if current_energy < lowest_energy:
lowest_energy = current_energy
best_mol = Chem.Mol(test_mol)
except Exception:
continue
if best_mol is None:
raise ValueError("Failed to generate optimized structure")
return best_mol
@staticmethod
def mol_to_sdf_bytes(mol):
"""Convert RDKit molecule to SDF file bytes"""
# First write to StringIO in text mode
sio = StringIO()
writer = Chem.SDWriter(sio)
writer.write(mol)
writer.close()
# Convert the string to bytes
return sio.getvalue().encode('utf-8')
def process_input(smiles_input=None, file_obj=None, show_linear=False,
show_segment_details=False, generate_3d=False, use_uff=False):
"""Process input and create visualizations using PeptideAnalyzer"""
analyzer = PeptideAnalyzer()
temp_dir = tempfile.mkdtemp() if generate_3d else None
structure_files = []
# Handle direct SMILES input
if smiles_input:
smiles = smiles_input.strip()
# First check if it's a peptide using analyzer's method
if not analyzer.is_peptide(smiles):
return "Error: Input SMILES does not appear to be a peptide structure.", None, None
try:
# Create molecule
mol = Chem.MolFromSmiles(smiles)
if mol is None:
return "Error: Invalid SMILES notation.", None, None
# Generate 3D structures if requested
if generate_3d:
generator = PeptideStructureGenerator()
try:
# Generate ETKDG structure
mol_etkdg = generator.generate_structure_etkdg(smiles)
etkdg_path = os.path.join(temp_dir, "structure_etkdg.sdf")
writer = Chem.SDWriter(etkdg_path)
writer.write(mol_etkdg)
writer.close()
structure_files.append(etkdg_path)
# Generate UFF structure if requested
if use_uff:
mol_uff = generator.generate_structure_uff(smiles)
uff_path = os.path.join(temp_dir, "structure_uff.sdf")
writer = Chem.SDWriter(uff_path)
writer.write(mol_uff)
writer.close()
structure_files.append(uff_path)
except Exception as e:
return f"Error generating 3D structures: {str(e)}", None, None, None
# Use analyzer to get sequence
segments = analyzer.split_on_bonds(smiles)
# Process segments and build sequence
sequence_parts = []
output_text = ""
# Only include segment analysis in output if requested
if show_segment_details:
output_text += "Segment Analysis:\n"
for i, segment in enumerate(segments):
output_text += f"\nSegment {i}:\n"
output_text += f"Content: {segment['content']}\n"
output_text += f"Bond before: {segment.get('bond_before', 'None')}\n"
output_text += f"Bond after: {segment.get('bond_after', 'None')}\n"
residue, mods = analyzer.identify_residue(segment)
if residue:
if mods:
sequence_parts.append(f"{residue}({','.join(mods)})")
else:
sequence_parts.append(residue)
output_text += f"Identified as: {residue}\n"
output_text += f"Modifications: {mods}\n"
else:
output_text += f"Warning: Could not identify residue in segment: {segment['content']}\n"
output_text += "\n"
else:
# Just build sequence without detailed analysis in output
for segment in segments:
residue, mods = analyzer.identify_residue(segment)
if residue:
if mods:
sequence_parts.append(f"{residue}({','.join(mods)})")
else:
sequence_parts.append(residue)
# Check if cyclic using analyzer's method
is_cyclic, peptide_cycles, aromatic_cycles = analyzer.is_cyclic(smiles)
three_letter = '-'.join(sequence_parts)
one_letter = ''.join(analyzer.three_to_one.get(aa.split('(')[0], 'X') for aa in sequence_parts)
if is_cyclic:
three_letter = f"cyclo({three_letter})"
one_letter = f"cyclo({one_letter})"
# Create cyclic structure visualization
img_cyclic = annotate_cyclic_structure(mol, three_letter)
# Create linear representation if requested
img_linear = None
if show_linear:
fig_linear = create_enhanced_linear_viz(three_letter, smiles)
buf = BytesIO()
fig_linear.savefig(buf, format='png', bbox_inches='tight', dpi=300)
buf.seek(0)
img_linear = Image.open(buf)
plt.close(fig_linear)
# Add summary to output
summary = "Summary:\n"
summary += f"Sequence: {three_letter}\n"
summary += f"One-letter code: {one_letter}\n"
summary += f"Is Cyclic: {'Yes' if is_cyclic else 'No'}\n"
#if is_cyclic:
#summary += f"Peptide Cycles: {', '.join(peptide_cycles)}\n"
#summary += f"Aromatic Cycles: {', '.join(aromatic_cycles)}\n"
if structure_files:
summary += "\n3D Structures Generated:\n"
for filepath in structure_files:
summary += f"- {os.path.basename(filepath)}\n"
return summary + output_text, img_cyclic, img_linear, structure_files if structure_files else None
except Exception as e:
return f"Error processing SMILES: {str(e)}", None, None, None
# Handle file input
if file_obj is not None:
try:
# Handle file content
if hasattr(file_obj, 'name'):
with open(file_obj.name, 'r') as f:
content = f.read()
else:
content = file_obj.decode('utf-8') if isinstance(file_obj, bytes) else str(file_obj)
output_text = ""
for line in content.splitlines():
smiles = line.strip()
if smiles:
# Check if it's a peptide
if not analyzer.is_peptide(smiles):
output_text += f"Skipping non-peptide SMILES: {smiles}\n"
continue
# Process this SMILES
segments = analyzer.split_on_bonds(smiles)
sequence_parts = []
# Add segment details if requested
if show_segment_details:
output_text += f"\nSegment Analysis for SMILES: {smiles}\n"
for i, segment in enumerate(segments):
output_text += f"\nSegment {i}:\n"
output_text += f"Content: {segment['content']}\n"
output_text += f"Bond before: {segment.get('bond_before', 'None')}\n"
output_text += f"Bond after: {segment.get('bond_after', 'None')}\n"
residue, mods = analyzer.identify_residue(segment)
if residue:
if mods:
sequence_parts.append(f"{residue}({','.join(mods)})")
else:
sequence_parts.append(residue)
output_text += f"Identified as: {residue}\n"
output_text += f"Modifications: {mods}\n"
else:
for segment in segments:
residue, mods = analyzer.identify_residue(segment)
if residue:
if mods:
sequence_parts.append(f"{residue}({','.join(mods)})")
else:
sequence_parts.append(residue)
# Get cyclicity and create sequence
is_cyclic, peptide_cycles, aromatic_cycles = analyzer.is_cyclic(smiles)
sequence = f"cyclo({'-'.join(sequence_parts)})" if is_cyclic else '-'.join(sequence_parts)
output_text += f"\nSummary for SMILES: {smiles}\n"
output_text += f"Sequence: {sequence}\n"
output_text += f"Is Cyclic: {'Yes' if is_cyclic else 'No'}\n"
if is_cyclic:
output_text += f"Peptide Cycles: {', '.join(peptide_cycles)}\n"
#output_text += f"Aromatic Cycles: {', '.join(aromatic_cycles)}\n"
output_text += "-" * 50 + "\n"
return output_text, None, None
except Exception as e:
return f"Error processing file: {str(e)}", None, None
return "No input provided.", None, None
iface = gr.Interface(
fn=process_input,
inputs=[
gr.Textbox(
label="Enter SMILES string",
placeholder="Enter SMILES notation of peptide...",
lines=2
),
gr.File(
label="Or upload a text file with SMILES",
file_types=[".txt"]
),
gr.Checkbox(
label="Show linear representation",
value=False
),
gr.Checkbox(
label="Show segment details",
value=False
),
gr.Checkbox(
label="Generate 3D structure (sdf file format)",
value=False
),
gr.Checkbox(
label="Use UFF optimization (may take long)",
value=False
)
],
outputs=[
gr.Textbox(
label="Analysis Results",
lines=10
),
gr.Image(
label="2D Structure with Annotations",
type="pil"
),
gr.Image(
label="Linear Representation",
type="pil"
),
gr.File(
label="3D Structure Files",
file_count="multiple"
)
],
title="Peptide Structure Analyzer and Visualizer",
description="""
Analyze and visualize peptide structures from SMILES notation:
1. Validates if the input is a peptide structure
2. Determines if the peptide is cyclic
3. Parses the amino acid sequence
4. Creates 2D structure visualization with residue annotations
5. Optional linear representation
6. Optional 3D structure generation (ETKDG and UFF methods)
Input: Either enter a SMILES string directly or upload a text file containing SMILES strings
Example SMILES strings (copy and paste):
```
CC(C)C[C@@H]1NC(=O)[C@@H](CC(C)C)N(C)C(=O)[C@@H](C)N(C)C(=O)[C@H](Cc2ccccc2)NC(=O)[C@H](CC(C)C)N(C)C(=O)[C@H]2CCCN2C1=O
```
```
C(C)C[C@@H]1NC(=O)[C@@H]2CCCN2C(=O)[C@@H](CC(C)C)NC(=O)[C@@H](CC(C)C)N(C)C(=O)[C@H](C)NC(=O)[C@H](Cc2ccccc2)NC1=O
```
```
CC(C)C[C@H]1C(=O)N(C)[C@@H](Cc2ccccc2)C(=O)NCC(=O)N[C@H](C(=O)N2CCCCC2)CC(=O)N(C)CC(=O)N[C@@H]([C@@H](C)O)C(=O)N(C)[C@@H](C)C(=O)N[C@@H](COC(C)(C)C)C(=O)N(C)[C@@H](Cc2ccccc2)C(=O)N1C
```
""",
flagging_mode="never"
)
# Launch the app
if __name__ == "__main__":
iface.launch(share=True)