Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 62.49 kDa 
• Atom Count: 4,383 
• Modelled Residue Count: 569 
• Deposited Residue Count: 569 
• Unique protein chains: 1

 3J4J

Model of full-length T. thermophilus Translation Initiation Factor 2 refined against its cryo-EM density from a 30S Initiation Complex map

• PDB DOI:  https://doi.org/10.2210/pdb3J4J/pdb
• EM Map EMD-2448: EMDB EMDataResource

• Classification: TRANSLATION
• Organism(s): Thermus thermophilus HB8
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2013-08-26 Released: 2013-09-25 
• Deposition Author(s): Simonetti, A., Marzi, S., Billas, I.M.L., Tsai, A., Fabbretti, A., Myasnikov, A., Roblin, P., Vaiana, A.C., Hazemann, I., Eiler, D., Steitz, T.A., Puglisi, J.D., Gualerzi, C.O., Klaholz, B.P.

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 11.5 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Involvement of protein IF2 N domain in ribosomal subunit joining revealed from architecture and function of the full-length initiation factor.

Simonetti, A., Marzi, S., Billas, I.M., Tsai, A., Fabbretti, A., Myasnikov, A.G., Roblin, P., Vaiana, A.C., Hazemann, I., Eiler, D., Steitz, T.A., Puglisi, J.D., Gualerzi, C.O., Klaholz, B.P.

(2013) Proc Natl Acad Sci U S A 110: 15656-15661

• PubMed: 24029017 
• DOI: https://doi.org/10.1073/pnas.1309578110
• Primary Citation of Related Structures:  
  3J4J


• PubMed Abstract: 
  

Translation initiation factor 2 (IF2) promotes 30S initiation complex (IC) formation and 50S subunit joining, which produces the 70S IC. The architecture of full-length IF2, determined by small angle X-ray diffraction and cryo electron microscopy, reveals a more extended conformation of IF2 in solution and on the ribosome than in the crystal. The N-terminal domain is only partially visible in the 30S IC, but in the 70S IC, it stabilizes interactions between IF2 and the L7/L12 stalk of the 50S, and on its deletion, proper N-formyl-methionyl(fMet)-tRNA(fMet) positioning and efficient transpeptidation are affected. Accordingly, fast kinetics and single-molecule fluorescence data indicate that the N terminus promotes 70S IC formation by stabilizing the productive sampling of the 50S subunit during 30S IC joining. Together, our data highlight the dynamics of IF2-dependent ribosomal subunit joining and the role played by the N terminus of IF2 in this process.

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Organizational Affiliation: 

Centre for Integrative Biology, Department of Integrated Structural Biology, Institute of Genetics and of Molecular and Cellular Biology, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche 7104, Institut National de la Santé de la Recherche Médicale U964, Université de Strasbourg, 67404 Illkirch, France.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Translation initiation factor IF-2	A	569	Thermus thermophilus HB8	Mutation(s): 0  Gene Names: infB, TTHA0699
UniProt
Find proteins for P48515 (Thermus thermophilus (strain ATCC 27634 / DSM 579 / HB8)) Explore P48515  Go to UniProtKB:  P48515

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 11.5 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
RECONSTRUCTION	EMAN	2
RECONSTRUCTION	IMAGIC

Structure Validation

Entry History 

Deposition Data

• Released Date: 2013-09-25 
Deposition Author(s): Simonetti, A., Marzi, S., Billas, I.M.L., Tsai, A., Fabbretti, A., Myasnikov, A., Roblin, P., Vaiana, A.C., Hazemann, I., Eiler, D., Steitz, T.A., Puglisi, J.D., Gualerzi, C.O., Klaholz, B.P.

Revision History  

• Version 1.0: 2013-09-25
  Type: Initial release
  
• Version 1.1: 2013-10-09
  Changes: Database references
• Version 1.2: 2018-07-18
  Changes: Data collection