Peptide–Recombinant Protein Conjugation

Conjugation to engineered, sequence-defined, recombinantly expressed proteins designed for controlled, reproducible peptide attachment.

High-control peptide–recombinant protein conjugates through integrated biosynthesis, recombinant protein expression, and site-specific conjugation.

Peptide–KLH conjugation Peptide–CRM197 conjugation MAP immunogens Blue carrier protein Peptide–BSA conjugates Peptide–OVA conjugation Program-aligned QC

Overview

Peptide–engineered recombinant protein conjugation is the covalent attachment of synthetic peptides to sequence-defined recombinant proteins that are intentionally designed to support controlled chemical modification. In contrast to traditional carrier protein formats, engineered recombinant scaffolds enable the rational placement of conjugation handles and reduction of competing reactive residues, improving homogeneity and reproducibility [1], [2].

Protein engineering strategies such as the introduction of site-specific residues, genetically encoded ligation motifs, or orthogonal functional groups allow peptide attachment with defined stoichiometry and predictable geometry. These approaches are widely used to generate homogeneous bioconjugates for functional, analytical, and mechanistic studies where batch-to-batch consistency is critical [1], [3].

This service focuses on recombinant protein scaffolds that are intentionally engineered to enable site-specific handles, defined stoichiometry, and homogeneous conjugates. When required, Bio-Synthesis integrates molecular biology → recombinant protein expression → purification → peptide conjugation → QC under a single workflow, aligning construct design with downstream conjugation chemistry and analytical requirements [2], [4].

Bio-synthesis (peptides + proteins) Engineered recombinant proteins Site-specific conjugation Defined stoichiometry Homogeneous conjugates Integrated expression & QC

Beyond peptide synthesis and conjugation, our bio-synthesis capabilities include recombinant protein expression services to produce engineered protein scaffolds that are “built for conjugation.” This integrated approach supports rational design decisions that preserve protein function, minimize heterogeneity, and simplify characterization [3], [5].

Workflow schematic of peptide–recombinant protein conjugation showing molecular biology, recombinant protein expression, purification, site-specific peptide attachment, and QC analysis.
Figure: Engineered workflow for peptide–recombinant protein conjugation showing protein design, expression, purification, site-specific attachment, and QC.

Conjugation chemistry, handle selection, and characterization depth are selected on a project-by-project basis based on peptide composition, protein scaffold design, and intended downstream use.

Core Capabilities

Protein engineering for conjugation

Build sequence-defined recombinant proteins optimized for predictable modification.

  • Introduce site-specific handles (e.g., engineered Cys positions)
  • Reduce competing reactive residues to limit heterogeneity
  • Optimize accessibility (placement, exposure, local environment)
  • Encode ligation motifs/tags when appropriate (project-dependent)
Controlled peptide attachment

Chemoselective and/or ligation-based strategies for defined stoichiometry and improved homogeneity.

  • Site-specific vs. rapid prototyping approaches
  • Defined stoichiometry (1:1 and controlled multi-valency)
  • Linker strategies to manage spacing and sterics
  • Project-fit purification to remove unreacted components
Recombinant protein expression (integrated)

Molecular biology + expression/purification aligned to the conjugation plan.

  • Gene design / cloning / construct strategy
  • Expression and purification for engineered scaffolds
  • Iterative optimization between design and conjugation outcome
  • Documentation and fit-for-purpose QC packages

If your goal is primarily immunogenicity (classic carrier formats), see Related services. This page is for functional, sequence-defined recombinant scaffolds designed for controlled conjugation.

Typical Workflow

Project planning (fastest start)
  • Peptide: sequence, modifications, preferred attachment site
  • Protein scaffold: target sequence or functional requirements
  • Stoichiometry goal: 1:1 vs multi-valent display
  • Constraints: activity retention, stability, buffer limits, scale

If you don’t have a construct yet, we can propose a design that is “built for conjugation.”

Execution steps
  • Design and build recombinant construct (as needed)
  • Express and purify sequence-defined protein scaffold
  • Perform conjugation (chemoselective or ligation-based)
  • Purify conjugate (case-by-case)
  • QC: intact mass + conjugation ratio; optional site confirmation

We can also start from your provided recombinant protein if it is compatible with the chosen chemistry.

Formats & Conjugation Methods (project-dependent)

Expand each section to view representative strategies, when to use them, and common design considerations.

Engineered recombinant proteins can be designed with genetically encoded conjugation handles to favor predictable, homogeneous attachment and to reduce off-target labeling.

Representative handle / concept Typical use cases Notes
Engineered single Cys 1:1 conjugates; controlled multi-valent designs Placement and accessibility are critical; reduces heterogeneity
Reduced competing residues Cleaner profiles and improved reproducibility Sequence design can simplify downstream purification/QC
Encoded ligation motifs (case-by-case) Precise attachment at a defined sequence position Best when you can engineer the scaffold from the start

Goal: move from “mixtures” toward defined conjugates that behave consistently across lots and assays.

Chemoselective strategies are selected based on peptide/protein functional groups, desired selectivity, and whether the project is in screening vs. an advanced reproducibility stage.

Approach Best for Notes
Thiol-selective (engineered Cys) Site-specific / controlled constructs Common path to homogeneous products
Amine-selective (Lys/N-terminus) Fast prototyping, broad compatibility Can be more heterogeneous; useful for early screening
Bioorthogonal (orthogonal handles) Sensitive proteins; multi-step workflows Enables orthogonal/dual-functionalization in some designs

Linkers/spacers are selected to manage peptide presentation, reduce steric hindrance, and tune stability.

  • Spacer length optimization (short vs extended)
  • Flexible vs constrained linkers (project-dependent)
  • Stability expectations (storage and assay conditions)

Characterization / QC (fit-for-purpose)

Common QC deliverables
  • Protein identity confirmation (pre-conjugation)
  • Conjugate confirmation (post-conjugation)
  • Conjugation efficiency and/or ratio assessment
  • Purity checks (case-by-case)
When to request “site confirmation”
  • Regulated or translational workflows
  • Strict 1:1 requirements
  • High sensitivity to geometry/sterics
  • Multi-site or orthogonal designs
Representative QC table
Check Purpose Notes
Intact mass Confirm peptide addition and gross composition Fast, informative for many constructs
Conjugation ratio / distribution Estimate stoichiometry and heterogeneity Method depends on construct and chemistry
Optional mapping Confirm attachment site(s) where required Often requested for site-specific programs
SEC / aggregation (optional) Assess size distribution and stability Useful for sensitive scaffolds or advanced programs

QC scope is project-dependent and aligned to your downstream decision points.

FAQ

Do you provide recombinant protein expression services in addition to conjugation?

Yes. We provide molecular biology and recombinant protein expression/purification services, enabling an integrated workflow from construct design through peptide conjugation and QC.

Is site-specific conjugation always required?

Not always. For early screening, a faster approach may be sufficient. For programs needing high reproducibility, defined stoichiometry, or strict geometry control, site-specific handle design is often recommended.

What should I send to start a project?

Provide the peptide sequence (and desired attachment site), your protein scaffold needs (or a target sequence), target stoichiometry, quantity, and intended application/assay conditions.

How do you confirm conjugation?

Typical confirmation includes intact mass and assessment of conjugation efficiency/ratio. Site confirmation (mapping) and additional stability/purity checks are available when required by the project.

Request a Quote

What to provide
  • Peptide sequence + desired attachment site (N-term / C-term / single-Cys / custom)
  • Recombinant protein scaffold details (sequence or functional requirements)
  • Stoichiometry target (1:1 or multi-valent display)
  • Preferred linker/handle (if any) and buffer constraints
  • Target quantity and intended application

Share your design details and constraints. We will recommend a feasible protein engineering and conjugation strategy with an appropriate QC plan aligned to your downstream use.

Fastest path

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Recommended reading

  • Site-selective modification of proteins for controlled conjugation: Nature Reviews Chemistry (2019). Nature article page
  • Protein engineering strategies enabling homogeneous bioconjugates: Chemical Society Reviews (review articles). RSC Chemical Society Reviews
  • Enzymatic ligation and genetically encoded tags for site-specific protein conjugation: Accounts of Chemical Research. ACS Accounts of Chemical Research
  • Recombinant protein design considerations for downstream chemical modification: Methods in Molecular Biology (protein engineering and expression volumes). Springer Methods in Molecular Biology
  • Analytical characterization of peptide–protein conjugates: Journal of Proteome Research and Analytical Chemistry. Journal of Proteome Research

References are provided for background and general design considerations. Access may depend on institutional or personal subscriptions.

Why Choose Bio-Synthesis

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