EF-Tu

EF-Tu_cycle

EF-Tu_conformations

Elongation factor thermo unstable (EF-Tu) is a protein that plays a crucial role in the elongation phase of protein synthesis in prokaryotes. It is a type of elongation factor and is essential for the accurate and efficient translation of mRNA into polypeptides.

Function

EF-Tu is responsible for the delivery of aminoacyl-tRNA to the ribosome during the elongation phase of translation. It binds to aminoacyl-tRNA and GTP, forming a ternary complex. This complex then interacts with the ribosome, facilitating the correct positioning of the aminoacyl-tRNA in the A site of the ribosome. Upon successful codon-anticodon pairing, GTP is hydrolyzed to GDP, and EF-Tu-GDP is released from the ribosome, allowing the aminoacyl-tRNA to participate in peptide bond formation.

Structure

EF-Tu is a GTP-binding protein and has a structure that is highly conserved among prokaryotes. It consists of three domains:

• Domain I: The GTP-binding domain, which is responsible for binding and hydrolyzing GTP.
• Domain II and III: These domains are involved in the interaction with aminoacyl-tRNA and the ribosome.

Mechanism

The mechanism of EF-Tu involves several steps: 1. EF-Tu binds to GTP and aminoacyl-tRNA, forming a ternary complex. 2. The ternary complex binds to the ribosome at the A site. 3. Correct codon-anticodon pairing triggers GTP hydrolysis. 4. EF-Tu-GDP is released from the ribosome, and the aminoacyl-tRNA is positioned for peptide bond formation. 5. EF-Tu is recycled by the action of elongation factor Ts (EF-Ts), which facilitates the exchange of GDP for GTP, allowing EF-Tu to participate in another round of elongation.

Importance in Translation

EF-Tu is essential for the fidelity and efficiency of protein synthesis. It ensures that only correctly charged tRNAs are delivered to the ribosome, thus maintaining the accuracy of translation. Mutations or malfunctions in EF-Tu can lead to errors in protein synthesis, which can have detrimental effects on the cell.

Related Proteins

EF-Tu is part of a family of elongation factors that includes elongation factor G (EF-G) and elongation factor Ts (EF-Ts). These proteins work together to ensure the proper elongation of the nascent polypeptide chain during translation.

See Also

• Translation (biology)
• Ribosome
• Aminoacyl-tRNA
• Elongation factor G
• Elongation factor Ts