Initial Primer Synthesis of a DNA Primase Monitored by Real-Time NMR Spectroscopy.

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• DNA replication initiation requires primers synthesized by primase enzymes.
• Archaeal pRN1 primase is essential for DNA replication.

Purpose of the Study:

• To investigate the real-time mechanism of initial dinucleotide formation by archaeal pRN1 primase.
• To elucidate the role of the helix-bundle domain (HBD) in primase activity.

Main Methods:

• Time-resolved nuclear magnetic resonance (NMR) spectroscopy in solution and solid-state.
• Utilizing nucleotide triphosphate analogues to slow down the reaction.
• ³¹P-detected and ¹H-detected NMR experiments.

Main Results:

• The helix-bundle domain (HBD) prepares substrates and transfers them to the catalytic domain.
• Dinucleotide formation kinetics were successfully monitored in real-time using solid-state NMR.
• Protein conformational changes during primer synthesis were observed, particularly within the HBD.

Conclusions:

• The HBD plays a critical role in substrate positioning and dinucleotide formation.
• Time-resolved NMR provides insights into the dynamic process of DNA replication initiation.
• The findings advance our understanding of primase enzyme mechanisms.