リボソームのA,P,E部位における23S rRNAとtRNAの相互作用
1Thimann Laboratories, University of California, Santa Cruz 95064.
Cell
|May 19, 1989
まとめ
この研究は,タンパク質合成中に,転送RNA (tRNA) がリボソームRNA (rRNA) とどのように相互作用するかを明らかにしています. 23S rRNAによるtRNAにおける特定の核酸保護は,CCA末端の相互作用と抗生物質の結合部位を示しています.
科学分野:
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
背景:
- リボソームは,メッセンジャーRNA (mRNA) からの遺伝情報をアミノ酸配列に変換し,タンパク質合成に不可欠です.
- 転送RNA (tRNA) 分子は,特定のアミノ酸をリボソームに供給し,正確な翻訳に不可欠です.
- 抗生物質はリボソーム機能を標的とし,細菌のタンパク質合成を阻害します.
研究 の 目的:
- A,P,E部位におけるtRNAと23SリボソームRNA (rRNA) の間の特定の相互作用を調査する.
- tRNA結合によって保護された23S rRNAの核酸領域とその機能的意義を特定する.
- リボソームとのtRNA相互作用を調節する延長因子Tu (EF-Tu) の役割を明らかにする.
主な方法:
- 23S rRNA.で保存されたヌクレオチドの化学的探査.
- リボソームA,P,E部位に結合するtRNAに対する保護パターンの分析.
- 3'-末端のCCAまたはアシル群が欠けている改変されたtRNAによる保護変化の調査.
- EF-Tu.GTP.aminoacyl-tRNA三元複合体の存在における保護パターンの検討.
主要な成果:
- 23S rRNAの3組の保存された核酸は,ペプチジルトランスファーゼセンターの近くにあるドメインVにあるA,P,EサイトでtRNA結合によって保護されています.
- クロランフェニコールなどの抗生物質で保護されている部分と重なり合っている保護された部位は,タンパク質合成に対する薬物干渉のメカニズムを示唆しています.
- tRNAの3'-末端のCCAまたはアシル群の除去により,特定の保護が廃止され,tRNA末端と23SrRNAの相互作用が確認されました.
- EF-Tu.GTP.aminoacyl-tRNAがリボソームに結合すると,EF-Tuが放出されるまでA部位の保護が妨げられ,tRNAの相互作用を調節する役割が示される.
結論:
- tRNAの3'-末端のCCAは,23S rRNAのペプチジルトランスファーゼ領域の保存された核酸と直接相互作用する.
- EF-Tuは,コードンの認識中にアミノアシル-tRNA 3'端とリボソームの相互作用を一時的にブロックし,翻訳的校正を容易にする.
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