Peptide Linkers for Site-Specific Conjugation and Lower sdAb Aggregation

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Solution Overview

Problem

Single-domain antibodies (sdAbs) used in multi-specific antibodies tend to aggregate, compromising their efficacy and safety, and conventional methods for antibody-drug conjugation suffer from low specificity and efficiency.

Innovation Solution

Development of specific peptide linkers with a transglutaminase-recognizable motif for site-specific conjugation, reducing fusion polypeptide aggregation and enhancing manufacturing and biological activities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional protein engineering approaches are used to mitigate aggregation, then aggregation is reduced, but the process becomes time-consuming and costly

Engineering Contradiction:

Improveaggregation reductionVSAvoidengineering time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The peptide linker is designed in advance with a specific conjugation motif (GGX1X2Q) that pre-establishes a site for transglutaminase-mediated conjugation. This preliminary design allows for rapid, site-specific attachment of linkers to fusion polypeptides without requiring extensive iterative protein engineering to achieve the desired aggregation reduction and conjugation specificity.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If conventional transglutaminase conjugation methods are used, then payload linkage is achieved, but specificity and efficiency are low

Engineering Contradiction:

Improveconjugation capabilityVSAvoidconjugation specificity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The peptide linker incorporates a localized conjugation motif (GGX1X2Q) at a specific position within the linker sequence. This local structural feature creates a dedicated recognition site for transglutaminase, enabling site-specific conjugation of the payload to the fusion polypeptide. The motif's specific amino acid sequence and spatial arrangement provide both the conjugation capability and the manufacturing precision required for controlled payload attachment.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The peptide linkers provide site-specific linkage, reducing aggregation and improving the efficiency and therapeutic effects of tandem single-domain multi-valent and/or multi-specific antibodies.

Implementation Method 1

Transglutaminase (TGase)-catalyzed conjugation is a conventional approach for linking a payload to an antibody

Methodology Applied

Scientific EffectTransglutaminase-catalyzed conjugation: Enzyme

Implementation Method 2

Such a conjugation motif allows for site-specific conjugation of a payload to a fusion polypeptide containing the peptide linker at the conjugation motif

Methodology Applied

Scientific EffectCovalent bonding: Chemical Bonding

Data Source

PatentUS20260027222A1Peptide linkers for construction and reducing aggregation of fusion polypeptides comprising such

Publication Date: 2026.01.29 SPARX BIOSCIENCE LIMITED

AI summary

A non-naturally occurring peptide linker, comprising a site-specific conjugation motif of GGX1X2Q, which allows for site-specific conjugation mediated by a transglutaminase; wherein each of X1 and X2 independently represents any naturally-occurring amino acid or one of X1 and X2 is absent; and wherein the non-naturally occurring peptide has a length of 9-20 amino acids. Also provided herein are fusion polypeptides such as tandem single-domain multi-specific antibodies containing such peptide linkers.