MYCBP2 Ligase Screening Assay Using Hydroxy Substrates

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Solution Overview

Problem

Current methods for profiling and modulating the activity of E3 ubiquitin ligases, such as MYCBP2, are limited, particularly in understanding their esterification activities and identifying effective modulators for therapeutic applications.

Innovation Solution

A screening assay is developed to study the interaction of MYCBP2 with hydroxy-containing substrates, utilizing covalent modification of catalytic cysteines C4520 and C4572 to identify modulators that can modulate MYCBP2 activity, which is essential for therapeutic and prophylactic use in conditions like axon degeneration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional methods for profiling E3 ubiquitin ligases are used, then the activity of E3 ligases can be assessed, but the ability to identify modulators for therapeutic applications is limited

Engineering Contradiction:
Improvetherapeutic application potentialVSAvoidmodulator identification capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces hydroxy-containing small molecules as proxy substrates that serve as intermediaries to detect and measure MYCBP2 esterification activity. These proxy substrates enable the identification of modulators by capturing the enzymatic interaction in a measurable format, thereby bridging the gap between conventional activity assessment and therapeutic modulator identification.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the measurement parameter from traditional ubiquitin conjugation assays to esterification activity measurement using hydroxy-containing substrates. This parameter change enables the detection of modulators that affect MYCBP2 activity, providing a new approach for identifying therapeutic candidates while maintaining reliability in assessing E3 ligase function.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If MYCBP2 activity is measured using traditional ubiquitin conjugation methods, then enzyme activity can be assessed, but esterification activity towards hydroxy-containing substrates cannot be detected

Engineering Contradiction:
Improvesubstrate rangeVSAvoidesterification activity detection
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent demonstrates that MYCBP2 possesses multi-functionality by exhibiting both traditional ubiquitin conjugation activity and esterification activity towards hydroxy-containing substrates. The development of a screening assay using hydroxy-containing small molecules enables the measurement of esterification activity, thereby expanding the substrate range and measurement capabilities while maintaining precision for detecting E3 ligase function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If a screening assay is developed to identify modulators of MYCBP2 activity, then therapeutic applications can be explored, but the complexity of the assay increases

Engineering Contradiction:
Improvemodulator screening capabilityVSAvoidassay complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs hydroxy-containing small molecules as disposable proxy substrates in the screening assay. These small molecules are inexpensive, easily synthesized, and can be readily discarded after use, thereby enabling high-throughput modulator screening without the complexity of handling complex protein substrates or requiring sophisticated detection systems.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

This approach allows for the identification of modulators that can effectively modulate MYCBP2 activity, providing potential therapeutic benefits for axon degeneration-associated injuries and disorders by exploiting the protein's unique esterification activity.

Implementation Method 1

Homologous to E6-AP Carboxy Terminus (HECT) E3s undergo a catalytic cysteine-dependent transthiolation reaction with the E2-ubiquitin covalently linked intermediate to form a covalently linked E3-ubiquitin intermediate.

Methodology Applied
Scientific EffectTransthiolation: Chemical Bonding

Implementation Method 2

The inventors have surprisingly found that this ligase exhibits esterification activity towards, for example, hydroxy containing substrates.

Methodology Applied
Scientific EffectEsterification: Chemical Bonding

Implementation Method 3

This leads to the intramolecular relay of ubiquitin from the cysteine residue to a further cysteine residue within MYCBP2 and then to its substrate.

Methodology Applied
Scientific EffectIntramolecular relay: Chemical Bonding

Data Source

PatentEP3765628B1Ligase screening assay
Publication Date: 2022.12.14 UNIVERSITY OF DUNDEE
  • EP3765628B1 patent drawingFigure 1(a)~1(b)
  • EP3765628B1 patent drawingFigure 1c
  • EP3765628B1 patent drawingFigure 2a~2f

AI summary

The present invention relates to a method for identifying a MYCBP2 modulator. Suitable modulators are identified by modulation of MYCBP2 ubiquitin E3 ligase activity via covalent modification of either of two catalytic cysteines (C4520 and C4572) or by impeding the motion of a newly presented dynamic, so-called, mediator loop region where C4520 resides. The present invention also relates to the use of hydroxy group- containing small molecules and peptides as proxy substrates for measuring MYCBP2 ligase activity and their use in the method of identifying modulators.