Mutant SubB Protein Glycan Binding Spectrum

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Solution Overview

Problem

Current subtilase cytotoxin B subunit proteins have limited ability to bind α2-6-linked N-glycolylneuraminic acid, restricting their application in detecting and targeting a broader spectrum of N-glycolylneuraminic acid-containing glycans, which are often expressed in cancer cells.

Innovation Solution

A mutant subtilase cytotoxin B subunit protein with specific amino acid deletions, such as ΔS106/ΔT107, is engineered to bind both α2-3-linked and α2-6-linked N-glycolylneuraminic acid, enhancing its affinity and specificity for these glycans while maintaining binding to α2-3-linked forms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the wild-type SubB protein structure is maintained, then binding to α2-3-linked N-glycolylneuraminic acid is preserved, but binding to α2-6-linked N-glycolylneuraminic acid is limited

Engineering Contradiction:

Improvebinding spectrum to different glycan linkagesVSAvoidbinding specificity to α2-3-linked Neu5Gc

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying specific amino acid residues in the SubB protein sequence (particularly in the glycan recognition site) to alter the binding properties. The mutations enable the protein to recognize both α2-3-linked and α2-6-linked N-glycolylneuraminic acid while maintaining sufficient specificity, thus expanding the binding spectrum without completely losing the original binding preference.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If amino acid deletions are introduced to expand binding capability, then binding to α2-6-linked Neu5Gc is improved, but protein structure stability may be affected

Engineering Contradiction:

Improveability to bind multiple glycan typesVSAvoidprotein structural integrity

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by introducing mutations only in specific regions of the SubB protein (the glycan recognition site) while leaving the overall protein structure intact. This localized modification approach allows the protein to gain new binding capabilities for different glycan linkages while maintaining the structural stability and functional integrity of the rest of the protein molecule.

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 mutant protein effectively detects and targets a wider range of N-glycolylneuraminic acid-containing glycans, including those in cancer cells, with improved recognition and binding capabilities compared to wild-type SubB, facilitating diagnostic and therapeutic applications.

Implementation Method 1

The present invention relates to a mutant subtilase cytotoxin B subunit protein (SubB) having an ability to bind α2-6-linked N-glycolylneuraminic acid while retaining the ability to bind α2-3-linked N-glycolylneuraminic acid

Methodology Applied

Scientific EffectGlycan binding:

Data Source

PatentEP3538544B1Subtilase cytotoxin b subunit mutant

Publication Date: 2024.03.27 GRIFFITH UNIVERSITY

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AI summary

A mutant subtilase cytotoxin B subunit protein is provided which can bind glycans having α2-3-linked N-glycolylneuraminic acid and glycans having α2-6-linked N-glycolylneuraminic acid. The mutant SubB protein has deletions of one or more of the amino acid sequence TTSTE and has a previously undescribed ability to bind glycans having α2-6-linked N-glycolylneuraminic acid, while not losing the ability to bind glycans having α2-3-linked N-glycolylneuraminic acid.