Specificity of ribonucleoprotein interaction determined by RNA folding during complex formulation

Area of Science:

• Molecular Biology
• Structural Biology
• RNA-protein interactions

Background:

• Proteins involved in pre-messenger RNA (pre-mRNA) processing often contain ribonucleoprotein domains.
• Ribonucleoproteins are crucial for RNA maturation through specific recognition of RNA elements.
• The human U1A protein regulates its expression by binding to a regulatory element in its 3'-untranslated region (UTR).

Purpose of the Study:

• To determine the nuclear magnetic resonance structure of the complex between the U1A protein RNA-binding domain and its 3'-UTR regulatory element.
• To elucidate the molecular mechanisms underlying the specific recognition between U1A protein and its target RNA.

Main Methods:

• Nuclear magnetic resonance (NMR) spectroscopy was employed to determine the structure of the protein-RNA complex.
• Analysis focused on the intermolecular interactions between the U1A ribonucleoprotein domain and the RNA hairpin.

Main Results:

• Specific recognition involves interactions between the variable loops of the U1A ribonucleoprotein domain and the helical regions of the RNA.
• Complex formation orders the flexible RNA single-stranded loop against the protein beta-sheet surface.
• The carboxy-terminal region of the U1A protein reorganizes to enhance surface complementarity and functional group recognition.

Conclusions:

• The study reveals the atomic details of U1A protein binding to its 3'-UTR regulatory RNA element.
• This structural insight explains the mechanism of autoregulation for the human U1A protein.
• Understanding these RNA-protein interactions is vital for comprehending gene regulation in RNA processing.