6FEC

Human cap-dependent 48S pre-initiation complex

これはPDB形式変換不可エントリーです。

6FEC の概要

• エントリーDOI: 10.2210/pdb6fec/pdb
• EMDBエントリー: 4242
• 分子名称: Eukaryotic translation initiation factor 3 subunit A, 18S ribosomal RNA, Messenger RNA (26-MER), ... (51 entities in total)
• 機能のキーワード: translation initiation, 48s complex, capped mrna, initiation factor 4b, start codon recognition, ribosome
• 由来する生物種: Homo sapiens (Human); 詳細
• タンパク質・核酸の鎖数: 50
• 化学式量合計: 2006440.16

構造登録者

Schaffitzel, C.,Schaffitzel, C. (登録日: 2017-12-31, 公開日: 2018-03-14, 最終更新日: 2024-10-16)

主引用文献

Eliseev, B.,Yeramala, L.,Leitner, A.,Karuppasamy, M.,Raimondeau, E.,Huard, K.,Alkalaeva, E.,Aebersold, R.,Schaffitzel, C.
Structure of a human cap-dependent 48S translation pre-initiation complex.
Nucleic Acids Res., 46:2678-2689, 2018

PubMed Abstract: Eukaryotic translation initiation is tightly regulated, requiring a set of conserved initiation factors (eIFs). Translation of a capped mRNA depends on the trimeric eIF4F complex and eIF4B to load the mRNA onto the 43S pre-initiation complex comprising 40S and initiation factors 1, 1A, 2, 3 and 5 as well as initiator-tRNA. Binding of the mRNA is followed by mRNA scanning in the 48S pre-initiation complex, until a start codon is recognised. Here, we use a reconstituted system to prepare human 48S complexes assembled on capped mRNA in the presence of eIF4B and eIF4F. The highly purified h-48S complexes are used for cross-linking/mass spectrometry, revealing the protein interaction network in this complex. We report the electron cryo-microscopy structure of the h-48S complex at 6.3 Å resolution. While the majority of eIF4B and eIF4F appear to be flexible with respect to the ribosome, additional density is detected at the entrance of the 40S mRNA channel which we attribute to the RNA-recognition motif of eIF4B. The eight core subunits of eIF3 are bound at the 40S solvent-exposed side, as well as the subunits eIF3d, eIF3b and eIF3i. elF2 and initiator-tRNA bound to the start codon are present at the 40S intersubunit side. This cryo-EM structure represents a molecular snap-shot revealing the h-48S complex following start codon recognition.

PubMed: 29401259
DOI: 10.1093/nar/gky054

実験手法

ELECTRON MICROSCOPY (6.3 Å)