Agent skill
bio-restriction-sites
Find restriction enzyme cut sites in DNA sequences using Biopython Bio.Restriction. Search with single enzymes, batches of enzymes, or commercially available enzyme sets. Returns cut positions for linear or circular DNA. Use when finding restriction enzyme cut sites in sequences.
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Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/data/restriction-sites
SKILL.md
Finding Restriction Sites
Core Pattern
python
from Bio import SeqIO
from Bio.Restriction import EcoRI, BamHI, HindIII, RestrictionBatch, Analysis
record = SeqIO.read('sequence.fasta', 'fasta')
seq = record.seq
# Single enzyme
sites = EcoRI.search(seq) # Returns list of cut positions
Search with Single Enzyme
python
from Bio.Restriction import EcoRI
sites = EcoRI.search(seq)
print(f'EcoRI cuts at positions: {sites}')
print(f'Number of sites: {len(sites)}')
# Check if enzyme cuts
if EcoRI.search(seq):
print('EcoRI cuts this sequence')
else:
print('EcoRI does not cut')
Search with Multiple Enzymes
python
from Bio.Restriction import RestrictionBatch, EcoRI, BamHI, HindIII, XhoI
batch = RestrictionBatch([EcoRI, BamHI, HindIII, XhoI])
# Method 1: batch.search()
results = batch.search(seq)
for enzyme, sites in results.items():
if sites:
print(f'{enzyme}: {sites}')
# Method 2: Analysis class
analysis = Analysis(batch, seq)
results = analysis.full()
Use Built-in Enzyme Collections
python
from Bio.Restriction import AllEnzymes, CommOnly
# All known enzymes (800+)
analysis = Analysis(AllEnzymes, seq)
# Commercially available only
analysis = Analysis(CommOnly, seq)
# Get results
results = analysis.full()
for enzyme, sites in results.items():
if sites:
print(f'{enzyme}: {sites}')
Linear vs Circular DNA
python
from Bio.Restriction import EcoRI, Analysis, RestrictionBatch
# Linear DNA (default)
sites_linear = EcoRI.search(seq, linear=True)
# Circular DNA (plasmid)
sites_circular = EcoRI.search(seq, linear=False)
# With Analysis class
batch = RestrictionBatch([EcoRI, BamHI])
analysis = Analysis(batch, seq, linear=False) # Circular
Filter Results
python
from Bio.Restriction import Analysis, CommOnly
analysis = Analysis(CommOnly, seq)
# Only enzymes that cut
analysis.print_that_cut()
# Only enzymes that don't cut (non-cutters)
analysis.print_that_dont_cut()
# Enzymes that cut once
analysis.print_once_cutters()
# Enzymes that cut twice
analysis.print_twice_cutters()
# Get as dictionary
cutters = analysis.only_cut()
non_cutters = analysis.only_dont_cut()
once_cutters = analysis.once_cutters()
twice_cutters = analysis.twice_cutters()
Get Enzyme Information
python
from Bio.Restriction import EcoRI
# Recognition sequence
print(f'Site: {EcoRI.site}') # GAATTC
print(f'Esite: {EcoRI.esite}') # Recognition with cut position
# Cut characteristics
print(f'Overhang: {EcoRI.ovhg}') # 4 (positive = 5' overhang)
print(f'Blunt: {EcoRI.is_blunt()}') # False
print(f'5\' overhang: {EcoRI.is_5overhang()}') # True
print(f'3\' overhang: {EcoRI.is_3overhang()}') # False
# Overhang sequence
print(f'Overhang seq: {EcoRI.ovhgseq}') # AATT
# Isoschizomers (same recognition, different cut)
print(f'Isoschizomers: {EcoRI.isoschizomers()}')
# Compatible enzymes (same overhang)
print(f'Compatible: {EcoRI.compatible_end()}')
Common Cloning Enzymes
python
from Bio.Restriction import (
EcoRI, BamHI, HindIII, XhoI, SalI, NotI, XbaI, SpeI,
NcoI, NdeI, BglII, PstI, KpnI, SacI, EcoRV, SmaI
)
common_enzymes = RestrictionBatch([
EcoRI, BamHI, HindIII, XhoI, SalI, NotI, XbaI,
NcoI, NdeI, BglII, PstI, KpnI, SacI, EcoRV, SmaI
])
analysis = Analysis(common_enzymes, seq)
results = analysis.full()
Access Enzymes by Name
python
from Bio.Restriction import AllEnzymes
# Get enzyme by string name
ecori = AllEnzymes.get('EcoRI')
sites = ecori.search(seq)
# Check if enzyme exists
if 'EcoRI' in AllEnzymes:
print('EcoRI is in database')
Search Multiple Sequences
python
from Bio import SeqIO
from Bio.Restriction import RestrictionBatch, EcoRI, BamHI
batch = RestrictionBatch([EcoRI, BamHI])
for record in SeqIO.parse('sequences.fasta', 'fasta'):
analysis = Analysis(batch, record.seq)
results = analysis.full()
print(f'{record.id}:')
for enzyme, sites in results.items():
if sites:
print(f' {enzyme}: {sites}')
Notes
- Positions are 1-based - first base is position 1
- Cut position - where enzyme cuts (between bases)
- Linear default - set
linear=Falsefor circular DNA - Case insensitive - recognition matches regardless of case
- Ambiguous bases - some enzymes recognize N, R, Y, etc.
Related Skills
- restriction-mapping - Visualize cut positions on sequence
- enzyme-selection - Choose enzymes by criteria
- fragment-analysis - Analyze resulting fragments
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