Dual-Specificity RNA Aptamers for Selective O-GlcNAcylation
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Solution Overview
Problem
Current methods are inadequate for studying the biological functions of O-GlcNAc on specific proteins due to the lack of tools to modify O-GlcNAcylation without affecting other proteins, and existing approaches complicate the interpretation of site-directed mutagenesis and antibody binding effects.
Innovation Solution
Development of dual-specificity RNA aptamers that modulate O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) activity to selectively increase or decrease O-GlcNAcylation on target proteins, using modular designed RNA aptamers with controlled binding via riboswitches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chemical inhibitors or genetic approaches targeting OGT and OGA are used, then O-GlcNAcylation can be modulated, but O-GlcNAcylation on thousands of proteins is changed simultaneously, making it difficult to study the biological functions of O-GlcNAc on a specific protein
Solution Approach 1:
The patent uses nanobody-tagged OGT or OGA constructs as intermediaries to selectively modify O-GlcNAcylation of target proteins in cells. The nanobodies serve as specific mediators that direct the enzymatic activity to predetermined target proteins, enabling selective modification without affecting global O-GlcNAcylation patterns.
Solution Approach 2:
The invention implements local quality by using nanobody tags that specifically recognize and bind to predetermined target proteins. This localization strategy ensures that OGT or OGA activity is confined to specific cellular locations and protein targets, rather than acting globally across all proteins.
2Measurement precision
If site-directed mutagenesis is used to convert serine or threonine to non-modifiable residues, then O-GlcNAcylation at specific sites can be prevented, but the interpretation of results is difficult due to crosstalk with phosphorylation and effects of antibody binding
Solution Approach 1:
The patent uses nanobody-tagged enzymes as intermediaries that specifically recognize target proteins without requiring site-directed mutagenesis. This approach preserves the native protein sequence and avoids the interpretational complications associated with mutagenesis and antibody binding effects.
Solution Approach 2:
The invention employs endogenous OGT and OGA enzymes tagged with nanobodies to perform the modification function. These enzymes naturally recognize their substrate sequences and perform O-GlcNAcylation or de-GlcNAcylation without requiring artificial modification of the target proteins, thereby maintaining physiological relevance.
3Measurement precision
If expressed protein ligation is used to generate full-length proteins with O-GlcNAc at defined sites, then in vitro assays can be performed, but the method requires cysteine residues at ligation sites and proteins are completely modified at defined sites limiting cellular application
Solution Approach 1:
The patent uses nanobody-tagged OGT or OGA as intermediaries to achieve site-specific O-GlcNAcylation in cellular systems. This approach eliminates the need for expressed protein ligation and cysteine residues, allowing the method to be applied broadly to any protein with appropriate O-GlcNAc recognition sequences.
Solution Approach 2:
The invention replaces the mechanical chemical ligation process with a biological recognition system. Instead of using cysteine-based chemical ligation to attach O-GlcNAc, the patent uses nanobody-protein interactions to direct enzymatic modification, substituting a chemical mechanism with a biological one that is more versatile and cell-compatible.
4Measurement precision
If nanobody-tagged OGT or OGA constructs are used to selectively modify O-GlcNAcylation of target proteins, then specificity is improved, but the tight and stable binding of these antibodies to target proteins makes sorting out biological effects of altered O-GlcNAcylation from antibody binding effects difficult
Solution Approach 1:
The patent uses nanobodies as intermediaries that bind to OGT or OGA rather than to the target proteins. This reverses the binding relationship: the nanobodies tag the modifying enzymes, not the target proteins. This approach maintains specificity while eliminating direct antibody-target protein interactions that complicate effect interpretation.
Data Source
AI summary
Disclosed herein are dual-specificity (DS) aptamers involving modular designed RNA that connect two aptamer motifs with a linker domain. In cells, they induce proximity between O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) and a designated protein, and increase or decrease O-GlcNAcylation on the substrate. These RNA aptamers have short half-lives in cells and their binding can be controlled by riboswitches.