ジャーナル: Proc Natl Acad Sci U S A / 年: 2013 タイトル: Involvement of protein IF2 N domain in ribosomal subunit joining revealed from architecture and function of the full-length initiation factor. 著者: Angelita Simonetti / Stefano Marzi / Isabelle M L Billas / Albert Tsai / Attilio Fabbretti / Alexander G Myasnikov / Pierre Roblin / Andrea C Vaiana / Isabelle Hazemann / Daniel Eiler / ...著者: Angelita Simonetti / Stefano Marzi / Isabelle M L Billas / Albert Tsai / Attilio Fabbretti / Alexander G Myasnikov / Pierre Roblin / Andrea C Vaiana / Isabelle Hazemann / Daniel Eiler / Thomas A Steitz / Joseph D Puglisi / Claudio O Gualerzi / Bruno P Klaholz / 要旨: 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 ...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.
T. thermophilus 30S initiation complex with 30S, fMet-tRNA, IF2-GTP, IF1, and mRNA
RIBOSOME
0
2
InitiationFactor2
1
緩衝液
名称: 10 mM HEPES, pH 7.5, 70 mM NH4Cl, 30 mM KCl, 8 mM magnesium acetate, 1 mM DTT pH: 7.5 詳細: 10 mM HEPES, pH 7.5, 70 mM NH4Cl, 30 mM KCl, 8 mM magnesium acetate, 1 mM DTT
試料
濃度: 0.5 mg/ml / 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES
急速凍結
装置: FEI VITROBOT MARK I / 凍結剤: ETHANE / 詳細: Vitrification carried out in liquid ethane