Protein-encapsulated fluorogenic probes for the selective detection of endogenous O-GlcNAcase (OGA)

Area of Science:

• Biochemistry
• Chemical Biology
• Molecular Biology

Background:

• O-GlcNAcase (OGA) plays a crucial role in cell growth, development, and disease.
• Developing sensitive and selective chemical tools is essential for studying OGA biology.

Purpose of the Study:

• To design and synthesize novel fluorogenic probes for selective detection of endogenous OGA activity in live cells.
• To enhance probe sensitivity and selectivity using a protein-encapsulation strategy with human serum albumin (HSA).

Main Methods:

• Design and synthesis of resorufin-based fluorogenic probes.
• Assembly of probes with HSA to form host-guest complexes.
• Small-angle X-ray scattering (SAXS) for structural analysis of the glycoprobe-HSA complex.
• Evaluation of probe selectivity for OGA over hexosaminidases (HEX) by modifying the glycan moiety.

Main Results:

• HSA encapsulation significantly enhanced probe sensitivity for OGA in aqueous solutions and live cells.
• Structural analysis provided insights into the glycoprobe-HSA complex.
• Modification of the glycan structure (propionyl group) conferred selectivity for OGA over HEX.
• Successful differentiation between cell lines with varying OGA and HEX levels.

Conclusions:

• The developed HSA-encapsulated probes offer a sensitive and selective method for detecting endogenous OGA activity in live cells.
• This approach enables the study of OGA's biological roles and potential as a therapeutic target.
• The strategy of protein encapsulation and glycan modification provides a versatile platform for developing targeted enzyme probes.