Gal-1 Variants Resisting Acidic and Oxidative Deactivation
Solution Overview
Problem
Native human Galectin-1 (Gal-1) is sensitive to acidic and oxidative conditions commonly found in inflammatory microenvironments, leading to its deactivation and reduced effectiveness in modulating immune responses.
Innovation Solution
Development of novel Gal-1 polypeptide variants with specific amino acid modifications, such as substitution of histidine to tyrosine or asparagine at position 52 and cysteine to serine at positions 2, 16, or 88, which confer resistance to acidic and oxidative conditions, maintaining immunomodulatory activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If native human Gal-1 is used in inflammatory microenvironments, then it can modulate immune responses through lectin-glycan signaling, but it becomes deactivated due to sensitivity to acidic and oxidative conditions
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of Gal-1 through site-directed mutagenesis. Specifically, histidine residues (particularly His52) are mutated to amino acids with different pKa values and chemical properties, and cysteine residues are mutated to eliminate disulfide bond formation. These parameter changes in the protein structure confer resistance to acidic and oxidative conditions while preserving immunomodulatory activity.
Solution Approach 2:
The patent converts the harmful sensitivity to acidic and oxidative conditions into a beneficial feature by creating mutants that are specifically engineered to withstand these conditions. The mutants H52Y, H52N, and the triple mutant C2SC16SH52Y transform the previously harmful inflammatory microenvironment conditions into a tolerable range, allowing Gal-1 to function effectively where native Gal-1 would be deactivated.
2Stability of the object's composition
If amino acid substitutions are made to confer resistance to acidic and oxidative conditions, then stability under inflammatory conditions is improved, but the molecular structure complexity increases
Solution Approach 1:
The patent applies local quality by making targeted mutations at specific positions in the Gal-1 amino acid sequence rather than modifying the entire protein. The mutations are localized to key residues: His52 (critical for pH sensitivity) and Cys2, Cys16, and Cys88 (critical for oxidation sensitivity). This localized approach achieves global stability improvement with minimal structural complexity increase.
Solution Approach 2:
The patent changes specific parameters of the amino acid sequence at critical positions. The His52 mutation to Tyr or Asn changes the pKa parameter and chemical properties at that position, while Cys to Ser mutations eliminate disulfide bond formation capability. These parameter changes are precise and targeted, achieving stability enhancement without excessive complexity.
Data Source
Figure 1A~1B
Figure 2~3E
Figure 4
AI summary
Galectin-1 polypeptide variants that include a mutation of the histidine residue corresponding to position 52 of the full-length amino acid sequence of native human Gal-1 as shown in SEQ ID NO: 1, the mutation being a substitution of the histidine to tyrosine or asparagine, providing resistance to acidosis otherwise resulting in deactivation of the native human Gal-1. The Galectin-1 polypeptide variants may include one or more additional mutation(s) of the cysteine residue corresponding to a position selected from 2, 16, 88, or combinations thereof of the full-length amino acid sequence of native human Gal-1 as shown in SEQ ID NO: 1, the additional mutation being a substitution of the cysteine to serine, and providing resistance to oxidation.