ジャーナル: Cell / 年: 2013 タイトル: Structure of the mammalian ribosomal 43S preinitiation complex bound to the scanning factor DHX29. 著者: Yaser Hashem / Amedee des Georges / Vidya Dhote / Robert Langlois / Hstau Y Liao / Robert A Grassucci / Christopher U T Hellen / Tatyana V Pestova / Joachim Frank / 要旨: Eukaryotic translation initiation begins with assembly of a 43S preinitiation complex. First, methionylated initiator methionine transfer RNA (Met-tRNAi(Met)), eukaryotic initiation factor (eIF) 2, ...Eukaryotic translation initiation begins with assembly of a 43S preinitiation complex. First, methionylated initiator methionine transfer RNA (Met-tRNAi(Met)), eukaryotic initiation factor (eIF) 2, and guanosine triphosphate form a ternary complex (TC). The TC, eIF3, eIF1, and eIF1A cooperatively bind to the 40S subunit, yielding the 43S preinitiation complex, which is ready to attach to messenger RNA (mRNA) and start scanning to the initiation codon. Scanning on structured mRNAs additionally requires DHX29, a DExH-box protein that also binds directly to the 40S subunit. Here, we present a cryo-electron microscopy structure of the mammalian DHX29-bound 43S complex at 11.6 Å resolution. It reveals that eIF2 interacts with the 40S subunit via its α subunit and supports Met-tRNAi(Met) in an unexpected P/I orientation (eP/I). The structural core of eIF3 resides on the back of the 40S subunit, establishing two principal points of contact, whereas DHX29 binds around helix 16. The structure provides insights into eukaryote-specific aspects of translation, including the mechanism of action of DHX29.
全体 : Cryo-electron microscopy structure of the mammalian 43S preinitia...
全体
名称: Cryo-electron microscopy structure of the mammalian 43S preinitiation complex bound to DHX29
要素
試料: Cryo-electron microscopy structure of the mammalian 43S preinitiation complex bound to DHX29
複合体: eukaryotic small ribosomal subunit
タンパク質・ペプチド: eukaryotic initiation factor 3
タンパク質・ペプチド: eukaryotic initiation factor 2
タンパク質・ペプチド: eukaryotic initiation factor 1
タンパク質・ペプチド: eukaryotic initiation factor 1A
タンパク質・ペプチド: DHX29
RNA: Transfer RNA
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超分子 #1000: Cryo-electron microscopy structure of the mammalian 43S preinitia...
超分子
名称: Cryo-electron microscopy structure of the mammalian 43S preinitiation complex bound to DHX29 タイプ: sample / ID: 1000 集合状態: One 40S binds one eIF3, one eIF2, one Met-tRNAiMet, and one DHX29 Number unique components: 5