Binding of eucaryotic elongation factor Tu to nucleic acids

Area of Science:

• Molecular Biology
• Protein Synthesis
• Biochemistry

Background:

• Eucaryotic elongation factor Tu (eEF-Tu) is crucial for protein synthesis.
• The interaction of eEF-Tu with nucleic acids is not fully understood.
• Ribosomal RNA (rRNA) plays a key role in ribosome function.

Purpose of the Study:

• To investigate the binding of eEF-Tu to various nucleic acids.
• To elucidate the functional implications of eEF-Tu-nucleic acid interactions.
• To explore the role of rRNA in eEF-Tu binding and GTPase activity.

Main Methods:

• Nucleic acid binding assays using different RNA and DNA polymers.
• Equilibrium centrifugation in an airfuge to study complex formation.
• GTPase activity assays to measure enzymatic function.
• Kinetic analysis of eEF-Tu GTPase in the presence of rRNA and polyribonucleotides.

Main Results:

• eEF-Tu exhibits high-affinity binding to rRNA, particularly 28 S rRNA, over tRNA.
• Binding is stronger to ribose-containing polymers (poly(G), poly(U)) than polydeoxyribonucleotides.
• eEF-Tu forms a quaternary complex with 28 S rRNA, aminoacyl-tRNA, and GTP.
• 28 S rRNA, poly(G), and poly(U) significantly stimulate eEF-Tu's intrinsic GTPase activity.
• Poly(G) binding to eEF-Tu reduces activation energy and increases Vmax for GTP hydrolysis.

Conclusions:

• eEF-Tu possesses distinct RNA binding sites, suggesting rRNA involvement in polysome recognition.
• rRNA may facilitate the binding of eEF-Tu.aminoacyl-tRNA.GTP complexes to ribosomes.
• eEF-Tu's GTPase activity is modulated by rRNA and specific polyribonucleotides.
• These findings provide insights into the role of eEF-Tu-rRNA interactions during protein synthesis.