Stapled Peptide Synthesis

α-helical peptides engineered for stability, target binding, and intracellular activity.

Overview

Stapled peptides: why they matter

Stapled peptides are conformationally constrained peptides designed to stabilize α-helical structure by covalently linking two side chains. By reducing flexibility, stapling can increase helical content, improve protease resistance, and strengthen target binding—especially for interfaces where helix geometry drives activity (common in protein–protein interactions)..

Bio-Synthesis manufactures stapled peptides using practical stapling routes—most commonly hydrocarbon stapling via ring-closing metathesis (RCM)—with optional labels/handles and a fit-for-purpose QC strategy. We focus on manufacturable designs: staple placement/spacing, sequence risk (aggregation/isomers), purification feasibility, and deliverables aligned to your application (screening vs assay-grade).

RCM hydrocarbon stapling i,i+4 / i,i+7 spacing Optional labels & handles Fit-for-purpose QC ISO 9001:2015/ISO13485:2016 45+ Years of Expertise U.S. Facilities - Texas
Helix stabilization

Stapling reinforces α-helical geometry to support function and target engagement.

Higher stability

Constraint often improves protease resistance and performance in biological matrices.

Design guidance

We recommend staple type/spacing that preserves key residues and reduces manufacturability risk.

Branched peptide synthesis schematic showing a lysine branching core with two to eight peptide arms (MAP-2, MAP-4, MAP-8) and dendrimer for multivalent epitope presentation.

Figure: Stapled peptide synthesis—side-chain crosslinking to stabilize α-helical structure (spacing and chemistry selected per sequence).

Stapled peptide synthesis Hydrocarbon stapled peptides Ring-closing metathesis (RCM) α-helical peptides PPI inhibitor peptides

Related services: Custom Cyclic Peptides, Peptide Modifications, Peptide Bioconjugation. For ready-made options, browse Catalog Peptides.

Common requests: MAP-2/4/8 peptide synthesis, hetero-branched peptides, multivalent ligP / probe constructs, and dendrimeric peptide designs (project-dependent).

Stapling chemistries we support

Hydrocarbon stapling (RCM)

Uses olefin-bearing non-natural residues and ring-closing metathesis to form a robust hydrocarbon staple that reinforces α-helical structure.

  • Common for i,i+4 and i,i+7 constraints
  • Often increases hydrophobicity—purification planned accordingly
  • Isomer complexity assessed case-by-case
Lactam bridges

Side-chain amide (e.g., Lys/Asp or Lys/Glu) that provides a stable, polar constraint for helix reinforcement.

  • Good option when RCM is not ideal
  • Can improve solubility relative to hydrocarbon staples (sequence-dependent)
  • Bridge positions tuned to preserve binding residues
Custom constraints

Alternative or hybrid constraints evaluated by sequence behavior and application requirements.

  • Multi-constraint designs when needed
  • Handles/labels integrated when compatible
  • Staged approach recommended for high complexity

Design guidance: staple spacing and placement

Stapled peptides work best when the staple reinforces helix geometry without replacing residues critical for binding. Share your target interface and peptide length, and we’ll recommend staple type and spacing (e.g., i,i+4 or i,i+7) plus a practical synthesis/purification/QC plan.

Design checklist
  • Provide sequence and intended α-helical region
  • Specify staple spacing (or ask us to recommend)
  • Identify residues that cannot be substituted
  • List required handles/labels and attachment positions
  • >Define fit-for-purpose purity/QC: screening vs assay-grade
Common risk factors
  • Hydrophobic sequences (staples can increase hydrophobicity)
  • Aggregation during SPPS or post-stapling processing
  • Isomeric products depending on chemistry and spacing
  • Solubility limits impacting purification and formulation

For challenging sequences, see Difficult Peptide Synthesis.

Biotin / fluorophores Click handles (azide/alkyne) Isotope labels PEG/spacers

Synthesis workflow

1) Design review

Confirm staple chemistry/spacing, substitution positions, handles, and success criteria.

2) SPPS assembly

Build the sequence with compatible non-natural residues and a protecting-group plan aligned to stapling.

3) Stapling & finishing

Perform stapling (e.g., RCM) under controlled conditions, then purify and complete QC.

What we optimize (practically)
  • Residue selection and spacing to preserve activity
  • Reaction conditions to favor desired stapled product
  • Minimize side products and isomer complexity
  • Purification strategy matched to hydrophobicity
  • Analytical plan to confirm identity and stapling
  • Documentation aligned to your downstream workflow

Specifications: what to define for a fast quote

Core specs
  • Sequence and target helical region
  • Staple type (RCM vs lactam) and spacing (i,i+4 / i,i+7)
  • Modifications/handles (biotin, dyes, azide/alkyne, cysteine)
  • Quantity (mg) and intended application
  • Purification/QC needs (desalt vs HPLC; MS; HPLC report)
Fastest quote checklist
  • One sequence per line (or attach a spreadsheet)
  • State “screening” vs “assay-grade”
  • Note solubility constraints (buffer / co-solvent limits) if known
  • Indicate required purity threshold (if strict)
  • Provide timeline and shipping requirements

Stapled peptide deliverables are sequence-dependent. We recommend fit-for-purpose purity/QC targets and a purification plan aligned to staple chemistry.

Parameter Typical options Notes / guidance
Staple chemistry RCM hydrocarbon staple; lactam bridge; custom constraints Selection depends on helix goal, solubility, and manufacturability.
Spacing i,i+4 or i,i+7 (others by request) Chosen to reinforce helix while preserving binding residues.
Purification Desalted or HPLC purified (where feasible) Stapling can increase hydrophobicity and impact HPLC resolution.
QC MS identity, HPLC profile/purity (when applicable) Additional analyses recommended for isomeric complexity as needed.
Options Labels, click handles, PEG/spacers, isotope labels Specify handle location and downstream chemistry.
Quantity 1–10 mg typical (more upon request) Yield depends on sequence risk and purification level.

QC & deliverables

Standard analytics
  • Mass spectrometry identity confirmation (MALDI-TOF or ESI-MS)
  • HPLC profile / purity assessment (sequence-dependent)
  • Certificate of Analysis (COA)

For highly hydrophobic stapled peptides, we align analytical conditions to solubility and chromatographic behavior.

Fit-for-purpose guidance
  • Assay-grade: prioritize purity and analytical clarity
  • Screening libraries: prioritize throughput and consistency
  • Lead optimization: staged QC as designs evolve

For conjugation-ready constructs, see Peptide Bioconjugation.

Applications

Protein–protein interactions

Stapled helices are frequently used to disrupt or mimic PPI interfaces (project-dependent).

Intracellular targets

Helix stabilization can support activity in challenging cellular environments.

Drug discovery & SAR

Use stapled variants to probe structure–activity relationships and improve performance.

Also explore: Peptide Libraries and Peptide Arrays.

FAQ

What is a stapled peptide?

A stapled peptide is a conformationally constrained peptide—often α-helical—where two side chains are covalently linked to reduce flexibility, improve stability, and enhance functional binding.

Which stapling chemistry should I choose (RCM vs lactam)?

RCM hydrocarbon stapling is widely used for α-helical stabilization. Lactam bridges provide a stable polar constraint. The best choice depends on your sequence, solubility needs, and target interface. We recommend a practical route and QC plan after design review.

What staple spacing is available (i,i+4, i,i+7)?

Common α-helical spacings include i,i+3, i,i+4, and i,i+7. Selection depends on helix length, residues required for binding, and manufacturability considerations such as aggregation and isomer formation.

How do you confirm stapling?

Stapling is typically confirmed by mass spectrometry and chromatographic behavior. When needed, additional analyses can be used for isomeric complexity or structure-sensitive applications.

Can you add labels or conjugation handles?

Yes. Depending on chemistry and sequence, we can incorporate biotin, fluorophores, isotope labels, and functional handles (azide/alkyne click, cysteine).

What information do you need for a fast quote?

Provide your sequence, preferred staple type/spacing (or ask us to recommend), any modifications/handles, target quantity, and intended application.

CONTACT

Speak to a Peptide Scientist

Share your sequence(s), preferred staple chemistry/spacing (or “recommend”), any modifications/handles, quantity, and intended application. We’ll propose practical specifications and a synthesis/purification/QC plan aligned to your goals.

Tip: If you’re converting a linear helix to a stapled design, tell us which residues must remain unchanged and your assay buffer constraints.

Why Choose Bio-Synthesis

Trusted by biotech leaders worldwide for over 40+ years of delivering high quality, fast and scalable synthetic biology solutions.