Archaeal-bacterial chimeric RNase P RNAs: towards understanding RNA's architecture, function and evolution.

Area of Science:

• Molecular Biology
• Evolutionary Biology
• Biochemistry

Background:

• Archaeal RNase P has higher protein content and lower RNA-alone activity than bacterial RNase P.
• RNase P is essential for cell viability, catalyzing precursor tRNA maturation.

Purpose of the Study:

• To investigate the functional interchangeability of archaeal and bacterial RNase P RNA catalytic domains.
• To understand the structural and evolutionary adaptations in RNase P RNA.

Main Methods:

• Construction of a chimeric P RNA combining archaeal and bacterial RNase P RNA domains.
• Functional assessment of the chimeric P RNA in Escherichia coli cells.
• Analysis of structural modifications and interdomain contacts required for function.

Main Results:

• An archaeal RNase P RNA catalytic domain, with specific alterations, functionally replaced the E. coli catalytic domain.
• Restoration of L9-P1 and introduction of L18-P8 interdomain contacts were crucial for chimeric P RNA function.
• Chimeric P RNA exhibited reduced cellular levels in E. coli, necessitating protein overexpression.

Conclusions:

• The catalytic domains of type A bacterial and archaeal P RNAs are largely conserved evolutionarily.
• Archaeal RNase P likely evolved protein-protein contacts to replace the L18-P8 RNA-RNA interaction.
• Functional complementation demonstrates conserved RNA structure and highlights divergent evolutionary paths in RNase P.