酵母的Shu蛋白復(fù)合物，是由Shu1,、Shu2、Psy3和Csm2幾種蛋白組成,，它通過偶聯(lián)復(fù)制后修復(fù)與同源重組,，維持了基因組的穩(wěn)定性。
然而,，由于缺乏對Shu蛋白的生化及結(jié)構(gòu)信息,，它們在該通路中精確的作用還不明確。近日,，中國科學(xué)技術(shù)大學(xué)滕脈坤課題組解析了Psy3-Csm2復(fù)合體在1.9 埃分辨率的晶體結(jié)構(gòu),。
晶體結(jié)構(gòu)表明，Psy3與Csm2主要通過一個疏水核心形成了一個異二聚體,。出乎預(yù)料的是,，Psy3和Csm2都有一個相似的非常類似于Rad51的ATPase核心結(jié)構(gòu)域。
Psy3和Csm2的L2環(huán)與Rad51的結(jié)構(gòu)非常類似,，它賦予了Shu復(fù)合體DNA結(jié)合活性,。與Rad51一樣，Shu復(fù)合體似乎通過非特異性的結(jié)合到DNA上,，形成了一個核蛋白纖絲 ,。
基于結(jié)構(gòu)突變研究表明了Shu復(fù)合體的DNA結(jié)合活性，而且這對修復(fù)甲磺酸甲酯引起的DNA損傷是必須的,。該發(fā)現(xiàn)對研究Shu復(fù)合體介導(dǎo)的Srs2的調(diào)節(jié)奠定了很好的基礎(chǔ),。相關(guān)論文發(fā)表在3月30日的The journal of Biological Chemistry。
滕脈坤教授是中國科學(xué)技術(shù)大學(xué)生命科學(xué)學(xué)院黨總支書記兼副院長,。多年從事生物大分子晶體學(xué)和結(jié)構(gòu)生物學(xué)研究,，曾從事DNA寡聚核苷酸及其DNA-藥物復(fù)合物的晶體學(xué)；病毒晶體學(xué)；T-細(xì)胞受體及其復(fù)合物的晶體學(xué),；葡萄糖異構(gòu)酶蛋白質(zhì)工程等研究工作,。目前主要進(jìn)行真核生物轉(zhuǎn)錄調(diào)控、基因損傷修復(fù),、囊泡形成相關(guān)蛋白質(zhì)及其復(fù)合物的結(jié)構(gòu)與功能關(guān)系研究,，同時(shí)關(guān)注天然蛇毒毒素蛋白對各類離子通道的調(diào)控機(jī)理研究,。（生物谷Deepblue編譯）
doi: 10.1074/jbc.M111.334698
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Structural analysis of Shu proteins reveals a DNA-binding role essential for resisting damage
Yuyong Tao, Xu Li, Yiwei Liu, Jianbin Ruan, Shali Qi, Liwen Niu and Maikun Teng.
The yeast Shu complex, consisting of the proteins Shu1, Shu2, Psy3 and Csm2, maintains genomic stability by coupling post-replication repair to homologous recombination.However, a lack of biochemical and structural information on the Shu proteins precludes revealing their precise roles within the pathway. Here we report the 1.9 A crystal structure of the Psy3-Csm2 complex.The crystal structure shows that Psy3 forms a heterodimer with Csm2 mainly through a hydrophobic core. Unexpectedly, Psy3 and Csm2 share a similar architecture which closely resembles the ATPase core domain of Rad51.The L2 loop present in Psy3 and Csm2 is similar to that of Rad51, and confers the DNA-binding activity of the Shu complex. As with Rad51, the Shu complex appears to form a nucleoprotein filament by binding non-specifically to DNA.Structure-based mutagenesis studies have demonstrated that the DNA-binding activity of the Shu complex is essential for repair of the methyl methanesulfonate-induced DNA damage. Our findings provide good foundations for the understanding of the Srs2 regulation by the Shu complex.
