Pentaphosphorylated magic spot nucleotides: chemoenzymatic synthesis and disassembly-based sensing

Area of Science:

• Biochemistry
• Molecular Biology
• Chemical Biology

Background:

• Magic spot nucleotides (MSNs), including (p)ppGpp and (p)ppApp, are crucial in bacterial stress response.
• Current methods for synthesizing and detecting MSNs are limited, hindering research.

Purpose of the Study:

• To develop a scalable synthesis for natural and functionalized pentaphosphorylated MSNs.
• To create a selective and water-compatible fluorescence probe for MSN detection.

Main Methods:

• Chemo-enzymatic synthesis using cyclic pyrophosphoryl phosphoramidite (cPyPA) and RNase T2 hydrolysis.
• Development of a metal-ligand disassembly fluorescence probe utilizing an Fe(III)-salen complex.

Main Results:

• Achieved preparative synthesis of 3'-monophosphates (ppAp, ppGp) and pentaphosphorylated MSNs (pppApp, pppGpp).
• The fluorescence probe selectively detects MSNs with 2-3 fold selectivity over other nucleotides.
• Probe demonstrates sensitivity to MSNs with 3'- and 5'-pyrophosphate groups and detects enzymatically generated ppGpp in vitro.

Conclusions:

• Established a robust synthesis for pentaphosphorylated MSNs.
• Developed a practical fluorescence sensor for selective MSN detection.
• These advancements provide tools for further bacterial stress signaling research.