哺乳類 eIF3 の構造は,43S 初期化複合体の文脈で

Amedee des Georges¹, Vidya Dhote², Lauriane Kuhn³

¹HHMI, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, USA.

Nature

|September 8, 2015

まとめ

研究者は43S複合体と結合した真核転化開始因子3 (eIF3) の構造を視覚化した. これは,タンパク質合成中にリボソームがメッセンジャーRNA (mRNA) に結合し,スキャンする方法に関する新しい洞察を提供します.

科学分野:

分子生物学
構造生物学
生物化学

背景:

ユカリオットの翻訳の開始は,複数の要因を含む複雑なプロセスです.
43S複合体は,40Sリボソームサブユニットと初期因子を含め,mRNAを結合してスタートコドンを見つけます.
構造化されたmRNAは,効率的なスキャンのためにDEXHボックスタンパク質DHX29を必要とします.

研究の目的:

DHX29結合の43S複合体内のeIF3 PCI/MPNコアの冷凍電子顕微鏡構造を決定する.
eIF3コアと43S複合体とのサブユニット組織と相互作用を明らかにする.
mRNAのリボソーム結合とスキャンの構造的基礎を理解する.

主な方法:

クリオ電子顕微鏡 (cryo-EM) で約6 Åの解像度で
eIF3のコアと周辺のサブユニットのほぼ完全なポリアラニンレベルのモデル構築.

主要な成果:

この構造は,eIF3 PCI/MPNコアの組織と43S複合体との相互作用を明らかにする.
eIF3のコアサブユニットと2つの周辺サブユニットの詳細なモデルが構築されました.
mRNA結合とスキャンにおけるeIF3とDHX29の役割に関する洞察を得られた.

結論:

この構造は,翻訳開始の文脈でeIF3の高解像度ビューを提供します.
この構造情報は,mRNA-リボソームの相互作用とスキャンのメカニズムを理解するために不可欠です.
この発見は,真核生物の遺伝子発現の調節に関する我々の知識に寄与する.

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