Describe and give the results of an experiment that shows...

Name: Problem 16, Chapter 18: Molecular Biology
Uploaded: 2021-08-28T13:18:52-08:00
Duration: 2 min 24 s
Channel: Sana Riaz
Description: Describe and give the results of an experiment that shows that EF-G and GTP are both required for translocation. What are the effects of (a) substituting GDPCP for GTP, and (b) adding fusidic acid in this single-translocation event assay?

Describe and give the results of an experiment that shows that EF-G and GTP are both required for translocation. What are the effects of (a) substituting GDPCP for GTP, and (b) adding fusidic acid in this single-translocation event assay?

Key Concepts

Non-Hydrolyzable GTP Analogs (e.g., GDPCP)

Non-hydrolyzable GTP analogs such as GDPCP mimic GTP in structure and can bind to EF-G, but they cannot be hydrolyzed to GDP and inorganic phosphate. This important property is used to study the role of GTP hydrolysis in translocation; when GDPCP replaces GTP, the translocation process is halted because the energy-releasing step of GTP hydrolysis is absent, demonstrating that GTP hydrolysis is essential for proper ribosomal function.

Antibiotic Inhibition (Fusidic Acid)

Fusidic acid is an antibiotic that targets EF-G by preventing its release from the ribosome after GTP hydrolysis. By locking EF-G in place, fusidic acid interrupts the normal cycling of EF-G binding and dissociation, thereby inhibiting the translocation step. This provides insight into the dynamics of EF-G action and underscores the importance of both GTP hydrolysis and subsequent EF-G release for efficient protein synthesis.

Translocation

Translocation refers to the movement of the ribosome along the mRNA during protein synthesis, allowing the decoding of successive codons. This process is essential for accurately and efficiently synthesizing proteins by shifting the positions of tRNAs from the A site to the P site and from the P site to the E site on the ribosome.

Elongation Factor G (EF-G) and GTP Hydrolysis

EF-G is a crucial protein factor in the translation process whose role is to catalyze the translocation step. It binds to the ribosome in complex with the nucleotide GTP. The hydrolysis of GTP provides the necessary energy to drive the conformational changes in the ribosome that enable the movement of tRNA and mRNA, ensuring that protein synthesis proceeds correctly.

Please give Ace some feedback