3J4J

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

Summary for 3J4J

• Entry DOI: 10.2210/pdb3j4j/pdb
• Related: 1D1N 4B3X 4B48 4KJZ
• EMDB information: 2448
• Descriptor: Translation initiation factor IF-2 (1 entity in total)
• Functional Keywords: if2, gtp-binding protein, fmet-trna binding, ribosome binding, translation
• Biological source: Thermus thermophilus
• Total number of polymer chains: 1
• Total formula weight: 62494.47

Authors

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. (deposition date: 2013-08-26, release date: 2013-09-25, Last modification date: 2024-02-21)

Primary citation

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.
Involvement of protein IF2 N domain in ribosomal subunit joining revealed from architecture and function of the full-length initiation factor.
Proc.Natl.Acad.Sci.USA, 110:15656-15661, 2013

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.

PubMed: 24029017
DOI: 10.1073/pnas.1309578110

Experimental method

ELECTRON MICROSCOPY (11.5 Å)