來自加州理工學(xué)院的研究人員近期接連破解了一蛋白機(jī)制之謎,，發(fā)現(xiàn)了泛素如何添加到控制細(xì)胞周期的特異性蛋白上的機(jī)制,，該項(xiàng)成果發(fā)表在近期Science權(quán)威刊物上。
研究人員分析了大腸桿菌中的信號(hào)識(shí)別顆粒（signal recognition particle,SRP）途徑,，發(fā)現(xiàn)機(jī)體能通過一系列的檢測點(diǎn)排除錯(cuò)誤,，從而確保蛋白靶向的精確性,。
正確的蛋白定位對(duì)于所有的細(xì)胞來說都是至關(guān)重要的,，但是科學(xué)家們對(duì)于蛋白靶向途徑中如何保存高度的忠實(shí)性的機(jī)制了解并不多。為了解開這一迷題,，在這篇文章中,，研究人員針對(duì)SRP途徑展開了研究，SRP途徑是一個(gè)高度保守的蛋白靶向途徑,，先后在真核生物,、原核生物和古細(xì)菌中被發(fā)現(xiàn)，在原核生物中SRP途徑主要由Ffh,、FtsY和scRNA組成,。
研究人員通過生物物理分析方法,，發(fā)現(xiàn)機(jī)體能通過一系列的檢測點(diǎn)排除錯(cuò)誤，從而確保蛋白靶向的精確性,。這種機(jī)制也許能應(yīng)用到其它選擇性的信號(hào)識(shí)別途徑中,。(生物谷Bioon.com)
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Science DOI: 10.1126/science.1186743
Sequential Checkpoints Govern Substrate Selection During Cotranslational Protein Targeting
Xin Zhang, Rumana Rashid,* Kai Wang, Shu-ou Shan
Proper protein localization is essential for all cells. However, the precise mechanism by which high fidelity is achieved is not well understood for any protein-targeting pathway. To address this fundamental question, we investigated the signal recognition particle (SRP) pathway in Escherichia coli, which delivers proteins to the bacterial inner membrane through recognition of signal sequences on cargo proteins. Fidelity was thought to arise from the inability of SRP to bind strongly to incorrect cargos. Using biophysical assays, we found that incorrect cargos were also rejected through a series of checkpoints during subsequent steps of targeting. Thus, high fidelity of substrate selection is achieved through the cumulative effect of multiple checkpoints; this principle may be generally applicable to other pathways involving selective signal recognition.
Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
* Present address: Department of Molecular Medicine, City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA.
