Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Initiation of Translation02:33

Initiation of Translation

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...
Initiation of Translation02:33

Initiation of Translation

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...
Translation in Prokaryotes01:29

Translation in Prokaryotes

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...
Termination of Translation01:44

Termination of Translation

The large ribosomal subunit has several important structures essential to translation. These include the peptidyl transferase center (PTC) - which is the site where the peptide bond is formed - and a large, internal, water-filled tube through which the nascent polypeptide moves. This latter structure is called the Peptide Exit Tunnel, and it begins at the PTC and spans the body of the large ribosomal subunit. During translation, as the nascent polypeptide chain is synthesized, it passes through...
Leaky Scanning02:28

Leaky Scanning

During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA.  Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
Improving Translational Accuracy02:07

Improving Translational Accuracy

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...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Translation initiation by the Kozak mRNA sequence is based on a conformational readout on the ribosome.

Nature communications·2026
Same author

Cryo-EM Structure of the C. Elegans Septin Tetramer Reveals a Revised Architecture and Conserved Positional Orthology.

Journal of molecular biology·2026
Same author

RanBP2-dependent annulate lamellae drive nuclear pore assembly and nuclear expansion.

Nature communications·2026
Same author

Extended Shine-Dalgarno motifs govern translation initiation in Staphylococcus aureus.

Nature communications·2026
Same author

The plastisphere and river systems as reservoirs for antibiotic resistant bacteria.

Frontiers in microbiology·2026
Same author

Explicit correction of severely non-uniform distributions of cryo-EM views.

Acta crystallographica. Section D, Structural biology·2026

Related Experiment Video

Updated: Jul 2, 2026

Toeprinting Analysis of Translation Initiation Complex Formation on Mammalian mRNAs
10:37

Toeprinting Analysis of Translation Initiation Complex Formation on Mammalian mRNAs

Published on: May 10, 2018

Structure of the 30S translation initiation complex.

Angelita Simonetti1, Stefano Marzi, Alexander G Myasnikov

  • 1Institute of Genetics and of Molecular and Cellular Biology, Department of Structural Biology and Genomics, Illkirch F-67404, France.

Nature
|September 2, 2008
PubMed
Summary

Bacterial translation initiation involves precise positioning of fMet-tRNA(fMet) within the 30S initiation complex (30SIC) via interactions with initiation factors IF1 and IF2. This structural insight clarifies 70S initiation complex assembly and GTP hydrolysis activation.

More Related Videos

Rapid In Vivo Fixation and Isolation of Translational Complexes from Eukaryotic Cells
14:29

Rapid In Vivo Fixation and Isolation of Translational Complexes from Eukaryotic Cells

Published on: December 25, 2021

An In Vitro Single-Molecule Imaging Assay for the Analysis of Cap-Dependent Translation Kinetics
09:52

An In Vitro Single-Molecule Imaging Assay for the Analysis of Cap-Dependent Translation Kinetics

Published on: September 15, 2020

Related Experiment Videos

Last Updated: Jul 2, 2026

Toeprinting Analysis of Translation Initiation Complex Formation on Mammalian mRNAs
10:37

Toeprinting Analysis of Translation Initiation Complex Formation on Mammalian mRNAs

Published on: May 10, 2018

Rapid In Vivo Fixation and Isolation of Translational Complexes from Eukaryotic Cells
14:29

Rapid In Vivo Fixation and Isolation of Translational Complexes from Eukaryotic Cells

Published on: December 25, 2021

An In Vitro Single-Molecule Imaging Assay for the Analysis of Cap-Dependent Translation Kinetics
09:52

An In Vitro Single-Molecule Imaging Assay for the Analysis of Cap-Dependent Translation Kinetics

Published on: September 15, 2020

Area of Science:

  • Molecular Biology
  • Structural Biology
  • Biochemistry

Background:

  • Translation initiation is a critical, rate-limiting step in protein synthesis.
  • Bacterial initiation involves selecting mRNA start sites and reading frames via initiation factors (IF1, IF2, IF3) and fMet-tRNA(fMet) binding to the 30S ribosomal subunit.
  • Formation of the 70S initiation complex (70SIC) requires 50S subunit joining and initiation factor release.

Purpose of the Study:

  • To visualize the structure of the 30S initiation complex (30SIC) including mRNA, fMet-tRNA(fMet), IF1, and GTP-bound IF2.
  • To elucidate the precise interactions stabilizing the 30SIC and their role in subsequent 70SIC assembly.
  • To understand the mechanism of GTP hydrolysis activation upon 50S subunit joining.

Main Methods:

  • Cryo-electron microscopy (cryo-EM)
  • Advanced particle separation techniques
  • Three-dimensional statistical analysis

Main Results:

  • Direct visualization of a 30SIC containing mRNA, fMet-tRNA(fMet), IF1, and GTP-bound IF2.
  • Identified two key interactions stabilizing the 30SIC: tRNA decoding stem in the 30S peptidyl site and IF2 carboxy-terminal domain with tRNA acceptor end.
  • Demonstrated that the GTP-binding domain of IF2 faces the 50S subunit's GTPase-activated center, explaining GTP hydrolysis activation.

Conclusions:

  • The precise positioning of fMet-tRNA(fMet) in the 30SIC is crucial for stable complex formation.
  • Structural insights reveal how IF2 mediates interactions essential for 70SIC assembly.
  • The study provides a structural basis for the rapid activation of GTP hydrolysis during 70SIC formation.