構造的な変化により,真核細胞の翻訳開始複合体によるスタートコドンの認識が可能になります

Tanweer Hussain¹, Jose L Llácer¹, Israel S Fernández¹

¹MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.

|November 24, 2014

まとめ

ユカリオットトランスレーション開始は,イニシアターtRNAがmRNAスキャンのためにPOUTコンフォームを採用することを含む. AUGが認識されると,PIN状態にイソメリズされ,コドン-アンチコドン複合体を安定させ,スタートコドン認識を容易にする.

科学分野:

分子生物学は分子生物学である.
構造生物学構造生物学とは
バイオケミストリーバイオケミストリー

背景:

ユカリオットトランスレーションの開始は,複数のタンパク質因子と40Sリボソームサブユニットを含む複雑なプロセスです.
イニシエーターtRNAは,最初に非正規のPOUTコンフォームに結合し,mRNAスキャンを可能にします.
スタートコドン認識は,PIN状態の構成的変化を誘発し,これは翻訳に不可欠です.

研究の目的:

ユカリオットの翻訳開始時のPIN状態の構造的基礎を解明する.
クリオ電子顕微鏡を用いて,PIN状態のイニシアターtRNAと酵母前始動複合体を視覚化します.
スタートコドン認識複合体の安定化における開始因子の役割を理解する.

主な方法:

クリオ電子顕微鏡 (cryo-EM) による酵母前始動複合体の再構築.
高解像度構造分析 (4.0 Å 解像度).

主要な成果:

PIN状態のイニシアターtRNAを持つ酵母前始動複合体の冷凍-EM構造が決定されました.
ユカリオット始動因子1A (eIF1A) のN端尾は,コドン-アンチコドン複合体を安定させる.
ユカリオット開始因子1 (eIF1) とユカリオット開始因子2 (eIF2) の形状の変化が観察され,eIF1の放出とコドン認識の開始を促進しました.
mRNAは,eIF2?,eIF1A,およびリボソームの要素と相互作用し,コンテキスト・ヌクレオチドの認識を可能にします.

結論:

PIN状態は,eIF1Aと主要なリボソーム要素を含む相互作用によって安定化されます.
eIF1とeIF2の構造的再編成は,スキャンからコドン認識への移行に不可欠です.
この構造は,リボソームがAUGスタートコドンとその周囲の文脈を翻訳開始時にどのように認識するかについての洞察を提供します.

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