H/ACA RNA蛋白質(zhì)復(fù)合物是普遍存在于真核生物和古細(xì)菌的一類保守的分子,，它們主要介導(dǎo)RNA的假尿嘧啶修飾，同時參與真核生物核糖體的裝配和脊椎動物端粒的合成,。目前對古細(xì)菌H/ACA 復(fù)合物的結(jié)構(gòu)己有詳細(xì)的了解,，但對真核生物復(fù)合物的結(jié)構(gòu)還了解很少。
2011年11月15日,，北京生命科學(xué)研究所的葉克窮實驗室在《Genes & Development》雜志發(fā)表了題為“Reconstitution and structural analysis of the yeast box H/ACA RNA-guided pseudouridine synthase”的論文,。
該論文首次利用重組表達(dá)的蛋白質(zhì)和RNA在體外組裝了有催化活性的酵母H/ACA復(fù)合物。利用這個重組系統(tǒng)，作者對H/ACA復(fù)合物的組裝方式,、催化活性和三維結(jié)構(gòu)進(jìn)行了深入的分析,。他們解析了包含其中三個蛋白質(zhì)組分的亞復(fù)合物的晶體結(jié)構(gòu)，并分析了復(fù)合物結(jié)構(gòu)和功能的關(guān)系,，發(fā)現(xiàn)了許多真核生物H/ACA復(fù)合物特有的結(jié)構(gòu)特征,。
該研究所博士研究生李爽是該論文的第一作者，段景琦博士,、李丹丹,、楊兵、董夢秋博士等人也參與了此研究工作,。葉克窮博士是本文通訊作者,。此項研究受中國科技部和北京市科委資助，在北京生命科學(xué)研究所完成,。(生物谷 Bioon.com)
doi:10.1101/gad.175299.111
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Reconstitution and structural analysis of the yeast box H/ACA RNA-guided pseudouridine synthase
Shuang Li, Jingqi Duan, Dandan Li, Bing Yang, Mengqiu Dong and Keqiong Ye,
Box H/ACA ribonucleoprotein particles (RNPs) mediate pseudouridine synthesis, ribosome formation, and telomere maintenance. The structure of eukaryotic H/ACA RNPs remains poorly understood. We reconstituted functional Saccharomyces cerevisiae H/ACA RNPs with recombinant proteins Cbf5, Nop10, Gar1, and Nhp2 and a two-hairpin H/ACA RNA; determined the crystal structure of a Cbf5, Nop10, and Gar1 ternary complex at 1.9 Å resolution; and analyzed the structure–function relationship of the yeast complex. Although eukaryotic H/ACA RNAs have a conserved two-hairpin structure, isolated single-hairpin RNAs are also active in guiding pseudouridylation. Nhp2, unlike its archaeal counterpart, is largely dispensable for the activity, reflecting a functional adaptation of eukaryotic H/ACA RNPs to the variable RNA structure that Nhp2 binds. The N-terminal extension of Cbf5, a hot spot for dyskeratosis congenita mutation, forms an extra structural layer on the PUA domain. Gar1 is distinguished from the assembly factor Naf1 by containing a C-terminal extension that controls substrate turnover and the Gar1–Naf1 exchange during H/ACA RNP maturation. Our results reveal significant novel features of eukaryotic H/ACA RNPs.
