¹H Parashift Probes for Ratiometric Detection of Nitroreductase

Area of Science:

• Coordination Chemistry
• Analytical Chemistry
• Biomolecular Detection

Background:

• Enzyme activity detection is crucial in diagnostics and research.
• Paramagnetic lanthanide complexes offer unique spectroscopic properties.
• Ratiometric detection methods enhance accuracy by minimizing signal variations.

Purpose of the Study:

• To synthesize and characterize novel lanthanide complexes for enzyme detection.
• To develop a ratiometric assay for the enzyme nitroreductase (NTR).
• To leverage paramagnetic shifts for sensitive and quantitative enzymatic activity measurements.

Main Methods:

• Synthesis and characterization of terbium (Tb) and dysprosium (Dy) complexes (TbL1, DyL1, TbL2).
• Utilizing paramagnetic chemical shift (PCS) of ¹H signals from a pyridine reporter group.
• Development of probe-specific pulse sequences for rapid NMR acquisition.

Main Results:

• Tb(III) and Dy(III) complexes induced significant paramagnetic contributions to chemical shifts (δ^PCS < -15).
• Distinct probe states ('off' and 'on') enabled ratiometric detection of NTR activity.
• A TbL2-specific pulse sequence achieved ratiometric NTR detection in under 1 minute.

Conclusions:

• Lanthanide complexes provide a zero-background platform for ratiometric enzyme detection.
• The developed probes offer rapid and quantitative measurement of nitroreductase activity.
• This approach holds promise for sensitive biosensing applications.