中國科學(xué)院院士,、南開大學(xué)校長饒子和領(lǐng)銜的研究小組今年年初在《病毒學(xué)雜志》（JVI）上公布研究成果：確定了兩個(gè)關(guān)鍵的ADRP位點(diǎn)晶體結(jié)構(gòu),，首次進(jìn)行了冠狀病毒ADRP位點(diǎn)系統(tǒng)結(jié)構(gòu)分析。
 
在這篇文章中,，研究人員確定了兩個(gè)關(guān)鍵ADRP位點(diǎn)的結(jié)晶結(jié)構(gòu),，包括I型人類冠狀病毒2299E和II型雞傳染性支氣管炎病毒，以及其各自與ADP核糖形成的復(fù)合物的結(jié)構(gòu),，從這些結(jié)構(gòu)分析得到的數(shù)據(jù)對(duì)于冠狀病毒的研究十分重要,，這也是首次對(duì)冠狀病毒ADRP位點(diǎn)進(jìn)行系統(tǒng)的結(jié)構(gòu)分析，為了解這一結(jié)構(gòu)域位點(diǎn)在冠狀病毒復(fù)制過程中扮演的角色打下了一個(gè)基礎(chǔ),。
 
近期,，饒子和研究小組又取得了一項(xiàng)重要的研究成果——確定了小鼠肝炎病毒A59(Hepatitis Virus A59)中非結(jié)構(gòu)蛋白4的C末端位點(diǎn)晶體結(jié)構(gòu)。這一研究成果公布在《公共科學(xué)圖書館·綜合》（PLoS One）雜志上,。
 
冠狀病毒的復(fù)制發(fā)生在內(nèi)質(zhì)網(wǎng)雙膜泡上,，研究發(fā)現(xiàn)，冠狀病毒復(fù)制復(fù)合物在膜上定位需要三個(gè)穿膜非結(jié)構(gòu)性蛋白：nsp3, nsp4和nsp6,，其中nsp4單獨(dú)表達(dá)后會(huì)結(jié)合在內(nèi)質(zhì)網(wǎng)膜上,，但是這種蛋白在感染細(xì)胞中則會(huì)定位在復(fù)制復(fù)合物上。該成果中,，研究人員確定了A59中nsp4的C末端親水位點(diǎn)晶體結(jié)構(gòu),，這對(duì)于進(jìn)一步了解這種蛋白在感染過程中的作用，以及整個(gè)病毒復(fù)制過程具有重要的意義,。

生物谷推薦原始出處：

Journal of Virology, January 2009, p. 1083-1092, Vol. 83, No. 2

Crystal Structures of Two Coronavirus ADP-Ribose-1''-Monophosphatases and Their Complexes with ADP-Ribose: a Systematic Structural Analysis of the Viral ADRP Domain

Yuanyuan Xu,1 Le Cong,1 Cheng Chen,1 Lei Wei,1 Qi Zhao,1 Xiaoling Xu,1 Yanlin Ma,2 Mark Bartlam,3 and Zihe Rao1,2,3*

Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China,1 National Laboratory of Biomacromolecules, Institute of Biophysics (IBP), Chinese Academy of Sciences, Beijing 100101, China,2 College of Life Sciences and Tianjin State Laboratory of Protein Science, Nankai University, Tianjin 300071, China3

The coronaviruses are a large family of plus-strand RNA viruses that cause a wide variety of diseases both in humans and in other organisms. The coronaviruses are composed of three main lineages and have a complex organization of nonstructural proteins (nsp's). In the coronavirus, nsp3 resides a domain with the macroH2A-like fold and ADP-ribose-1"-monophosphatase (ADRP) activity, which is proposed to play a regulatory role in the replication process. However, the significance of this domain for the coronaviruses is still poorly understood due to the lack of structural information from different lineages. We have determined the crystal structures of two viral ADRP domains, from the group I human coronavirus 229E and the group III avian infectious bronchitis virus, as well as their respective complexes with ADP-ribose. The structures were individually solved to elucidate the structural similarities and differences of the ADRP domains among various coronavirus species. The active-site residues responsible for mediating ADRP activity were found to be highly conserved in terms of both sequence alignment and structural superposition, whereas the substrate binding pocket exhibited variations in structure but not in sequence. Together with data from a previous analysis of the ADRP domain from the group II severe acute respiratory syndrome coronavirus and from other related functional studies of ADRP domains, a systematic structural analysis of the coronavirus ADRP domains was realized for the first time to provide a structural basis for the function of this domain in the coronavirus replication process.

PLoS ONE 4(7): e6217. doi:10.1371/journal.pone.0006217

Crystal Structure of the C-Terminal Cytoplasmic Domain of Non-Structural Protein 4 from Mouse Hepatitis Virus A59

Xiaoling Xu1, Zhiyong Lou1, Yanlin Ma1, Xuehui Chen1,2, Zhangsheng Yang2, Xiaohang Tong1,2, Qi Zhao1, Yuanyuan Xu1, Hongyu Deng2, Mark Bartlam3, Zihe Rao1,2,3*

1 Laboratory of Structural Biology, Tsinghua University, Beijing, China, 2 National Laboratory of Biomacromolecules, Institute of Biophysics (IBP), Chinese Academy of Sciences, Beijing, China, 3 College of Life Sciences and Tianjin Key Laboratory of Protein Science, Nankai University, Tianjin, China

Background

The replication of coronaviruses takes place on cytoplasmic double membrane vesicles (DMVs) originating in the endoplasmic reticulum (ER). Three trans-membrane non-structural proteins, nsp3, nsp4 and nsp6, are understood to be membrane anchors of the coronavirus replication complex. Nsp4 is localized to the ER membrane when expressed alone but is recruited into the replication complex in infected cells. It is revealed to contain four trans-membrane regions and its N- and C-termini are exposed to the cytosol.

Methodology/Principal Findings

We have determined the crystal structures of the C-terminal hydrophilic domain of nsp4 (nsp4C) from MHV strain A59 and a C425S site-directed mutant. The highly conserved 89 amino acid region from T408 to Q496 is shown to possess a new fold. The wild-type (WT) structure features two monomers linked by a Cys425-Cys425 disulfide bond in one asymmetric unit. The monomers are arranged with their N- and C-termini in opposite orientations to form an “open” conformation. Mutation of Cys425 to Ser did not affect the monomer structure, although the mutant dimer adopts strikingly different conformations by crystal packing, with the cross-linked C-termini and parallel N-termini of two monomers forming a “closed” conformation. The WT nsp4C exists as a dimer in solution and can dissociate easily into monomers in a reducing environment.

Conclusions/Significance

As nsp4C is exposed in the reducing cytosol, the monomer of nsp4C should be physiological. This structure may serve as a basis for further functional studies of nsp4.