Magnesium-binding architectures in RNA crystal structures: validation, binding preferences, classification and motif...

Area of Science:

• Biochemistry
• Structural Biology
• Computational Biology

Background:

• Magnesium ions (Mg2+) are essential for RNA folding, stability, and diverse biological functions.
• Understanding Mg2+ coordination is critical for deciphering RNA structure-function relationships.
• Previous studies have identified some Mg2+-binding motifs, but a systematic classification is lacking.

Purpose of the Study:

• To systematically analyze Mg2+-binding architectures in RNA structures.
• To develop a comprehensive classification system for Mg2+ coordination sites in RNA.
• To identify novel Mg2+-binding motifs in RNA.

Main Methods:

• Curated a benchmark dataset of 15,334 reliable Mg2+ binding sites from the Protein Data Bank (PDB).
• Analyzed normalized frequencies of RNA atom coordination in inner and outer spheres.
• Developed and applied a hierarchical classification system for Mg2+ binding sites.

Main Results:

• Identified 41 types of inner-sphere and 95 types of outer-sphere Mg2+ coordination patterns.
• Successfully applied the classification system to known Mg2+-binding motifs and detected them in new structures.
• Discovered seven novel Mg2+-binding motifs after analyzing the most populous site types.

Conclusions:

• The developed classification system provides a robust framework for analyzing Mg2+ interactions in RNA.
• The identification of novel Mg2+-binding motifs expands our understanding of RNA-metal ion interactions.
• This work facilitates further investigation into the role of magnesium in RNA biology and potential therapeutic applications.