Related Experiment Video
Updated: Nov 1, 2025
10:37
Toeprinting Analysis of Translation Initiation Complex Formation on Mammalian mRNAs
Published on: May 10, 2018
12.8K
The dynamic cycle of bacterial translation initiation factor IF3
Jose A Nakamoto1, Wilfredo Evangelista1, Daria S Vinogradova2,3
1Laboratory of Applied Biophysics and Biochemistry, Centre for Research and Innovation, Health Sciences Faculty, Universidad Peruana de Ciencias Aplicadas (UPC), Lima 15023, Peru.
Nucleic Acids Research
|June 23, 2021
Summary
Bacterial translation initiation factor IF3 dynamically adjusts its domains to ensure accurate mRNA decoding. Its movements are crucial for selecting initiator tRNA and completing the 70S initiation complex.
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- Initiation factor IF3 (IF3) is vital for bacterial mRNA translation initiation.
- IF3 enhances translation fidelity and speed.
- Understanding IF3's dynamic interactions is key to deciphering translation regulation.
Purpose of the Study:
- To elucidate the dynamic interplay between IF3 domains and their binding sites.
- To characterize the kinetic movements of IF3 during translation initiation.
- To reveal how IF3 ensures accurate mRNA translation.
Main Methods:
- Pre-steady state kinetics.
- Molecular modeling of initiation complexes.
- Analysis of available structural data.
Main Results:
- IF3 domains adapt their positions based on 30S ligand binding.
- IF1 and IF2 induce IF3 compaction, positioning its C-terminal domain (IF3C) at the P site.
- IF3's N-terminal domain (IF3N) forms a pocket for initiator tRNA, with transient accommodation during selection.
- Start codon decoding moves IF3C, rate-limiting initiation; 70S complex formation brings IF3 domains together before recycling.
Conclusions:
- IF3 exhibits a kinetic spectrum of movements crucial for translation initiation.
- Functional transitions of IF3 ensure accurate mRNA translation.
- IF3's dynamic nature is essential for efficient and precise protein synthesis initiation.
Related Concept Videos
02:33Initiation of Translation
35.8K
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
35.8K
02:33Initiation of Translation
7.1K
7.1K
01:29Translation in Prokaryotes
554
Prokaryote translation is a complex, highly coordinated process that converts genetic information from mRNA into functional proteins. It involves three stages: initiation, elongation, and termination, each facilitated by specific molecular components.Initiation of TranslationThe process begins with the assembly of the ribosomal subunits and initiation factors on the mRNA. In bacteria, the 30S ribosomal subunit recognizes the Shine-Dalgarno sequence in the mRNA, a conserved region upstream of...
554
02:07Improving Translational Accuracy
12.1K
Base complementarity between the three base pairs of mRNA codon and the tRNA anticodon is not a failsafe mechanism. Inaccuracies can range from a single mismatch to no correct base pairing at all. The free energy difference between the correct and nearly correct base pairs can be as small as 3 kcal/ mol. With complementarity being the only proofreading step, the estimated error frequency would be one wrong amino acid in every 100 amino acids incorporated. However, error frequencies observed in...
12.1K
01:29Coordination of Gene Expression Processes in Bacteria
282
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...
282
01:26Bacterial Protein Maturation
176
Bacterial protein maturation is a tightly regulated process that ensures newly synthesized polypeptides achieve correct functional conformations. This maturation involves a series of modifications, folding events, and quality control steps, often assisted by specialized chaperone proteins.N-Terminal ModificationsThe maturation of bacterial polypeptides begins cotranslationally as the polypeptide exits the ribosome. The first amino acid, N-formylmethionine (fMet), is typically modified at the...
176