Genetically encoded fluorescent probe for the selective detection of peroxynitrite

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Peroxynitrite is a critical reactive nitrogen species involved in cellular signaling pathways.
• Dysregulation of peroxynitrite contributes to various pathological conditions.
• Existing methods for detecting peroxynitrite have limitations in selectivity and physiological relevance.

Purpose of the Study:

• To develop a novel genetically encoded fluorescent probe for the selective detection of peroxynitrite.
• To engineer a probe capable of imaging peroxynitrite in live mammalian cells.
• To create a tool that distinguishes peroxynitrite from other reactive oxygen and nitrogen species.

Main Methods:

• Design and synthesis of a genetically encoded probe incorporating a boronic acid moiety.
• Site-specific introduction of the boronic acid into circularly permuted fluorescent proteins.
• Directed evolution through site-targeted random mutagenesis to optimize probe selectivity and sensitivity.
• Validation of probe performance in vitro and in genetically modified mammalian cells.

Main Results:

• Identification of pnGFP, a novel genetically encoded probe with high selectivity for peroxynitrite.
• Demonstration that pnGFP is largely unresponsive to other common cellular redox signaling molecules.
• Successful genetic introduction and imaging of peroxynitrite in mammalian cells at physiologically relevant concentrations.
• The probe exhibits robust fluorescence changes upon peroxynitrite binding.

Conclusions:

• pnGFP represents a significant advancement in the development of tools for studying reactive nitrogen species.
• The probe enables real-time imaging of peroxynitrite dynamics in living cells.
• This technology has potential applications in understanding cell signaling and disease pathogenesis involving peroxynitrite.