Elongation factor Tu: a molecular switch in protein biosynthesis

Area of Science:

• Molecular Biology
• Structural Biology
• Microbiology

Background:

• Elongation factor Tu (EF-Tu) is the most abundant protein in Escherichia coli.
• EF-Tu is a guanine nucleotide-binding protein essential for carrying amino acyl-tRNA to the ribosome during translation.
• Recent advances in biochemical, physico-chemical, and genetic methods have significantly improved understanding of EF-Tu.

Purpose of the Study:

• To elucidate the structural and functional characteristics of EF-Tu.
• To investigate the regulatory mechanisms governing the expression of EF-Tu encoding genes (tufB).
• To re-examine the role of EF-Tu in the elongation cycle and its regulation within the bacterial cell.

Main Methods:

• Crystallographic analysis at 2.6 A resolution.
• Site-directed mutagenesis.
• Biochemical, physico-chemical, and genetic methods.

Main Results:

• Structural and functional similarities were identified between the guanine nucleotide-binding domains of EF-Tu and human H-ras p21 protein.
• Diverse mechanisms regulating the expression of the two EF-Tu-encoding genes in E. coli, particularly tufB, were revealed.
• New insights into the functions of EF-Tu during the elongation cycle were obtained.

Conclusions:

• The study highlights significant structural and functional parallels between bacterial EF-Tu and human H-ras p21.
• Multiple regulatory pathways influence EF-Tu gene expression and protein activity in E. coli.
• A comprehensive understanding of EF-Tu's multifaceted regulatory mechanisms in bacteria has been advanced.