Functional and structural studies of the vaccinia virus virulence factor N1 reveal a Bcl-2-like anti-apoptotic protein.
Functional and structural studies of the vaccinia virus virulence factor N1 reveal a Bcl-2-like anti-apoptotic protein.
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DOI：
10.1099/vir.0.82772-0
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发表时间：
2007-06
期刊：
影响因子：
--
通讯作者：
Smith GL
中科院分区：
文献类型：
--
作者：
Cooray S;Bahar MW;Abrescia NGA;McVey CE;Bartlett NW;Chen RA;Stuart DI;Grimes JM;Smith GL
牛痘病毒（VACV）编码许多免疫调节蛋白，包括细胞凋亡抑制剂和先天免疫信号传导调节剂。VACV蛋白N1是一种细胞内同源二聚体，有助于病毒的毒力，并据报道抑制核因子（NF）-κB信号转导。然而，在用含有或不含有N1 L基因的重组病毒感染的细胞中，NF-κB B信号传导分析显示NF-κ B依赖性基因表达没有差异。考虑到N1促进病毒毒力，研究了N1的其他可能功能，这表明N1是用N1 L基因转染的细胞和VACV感染背景下的细胞凋亡的抑制剂。为了支持这一发现，病毒表达的N1与内源性促凋亡Bcl-2蛋白Bid、Bad和Bax以及通过转染表达的Bad和Bax共沉淀。此外，N1的晶体结构解析至2.9 nm分辨率（0.29 nm）。 值得注意的是，尽管N1与细胞蛋白没有序列相似性，但其三维结构与Bcl-xL和Bcl-2蛋白家族的其他成员非常相似。该结构还揭示了N1具有与其他抗凋亡Bcl-2蛋白的凹槽相似的组成性开放表面凹槽，其结合促凋亡Bcl-2家族成员的BH 3基序。BH 3肽到N1表面沟的分子建模，连同它们的物理化学性质的分析，表明肽识别的特异性的机制。这项研究说明了进化保守的结构，而不是序列，在蛋白质功能的重要性，并揭示了一种新的抗凋亡蛋白从正痘病毒。
Vaccinia virus (VACV) encodes many immunomodulatory proteins, including inhibitors of apoptosis and modulators of innate immune signalling. VACV protein N1 is an intracellular homodimer that contributes to virus virulence and was reported to inhibit nuclear factor (NF)-κB signalling. However, analysis of NF-κB signalling in cells infected with recombinant viruses with or without the N1L gene showed no difference in NF-κB-dependent gene expression. Given that N1 promotes virus virulence, other possible functions of N1 were investigated and this revealed that N1 is an inhibitor of apoptosis in cells transfected with the N1L gene and in the context of VACV infection. In support of this finding virally expressed N1 co-precipitated with endogenous pro-apoptotic Bcl-2 proteins Bid, Bad and Bax as well as with Bad and Bax expressed by transfection. In addition, the crystal structure of N1 was solved to 2.9 Å resolution (0.29 nm). Remarkably, although N1 shows no sequence similarity to cellular proteins, its three-dimensional structure closely resembles Bcl-xL and other members of the Bcl-2 protein family. The structure also reveals that N1 has a constitutively open surface groove similar to the grooves of other anti-apoptotic Bcl-2 proteins, which bind the BH3 motifs of pro-apoptotic Bcl-2 family members. Molecular modelling of BH3 peptides into the N1 surface groove, together with analysis of their physico-chemical properties, suggests a mechanism for the specificity of peptide recognition. This study illustrates the importance of the evolutionary conservation of structure, rather than sequence, in protein function and reveals a novel anti-apoptotic protein from orthopoxviruses.
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影响因子：
6.7
作者：
Loh J;Huang Q;Petros AM;Nettesheim D;van Dyk LF;Labrada L;Speck SH;Levine B;Olejniczak ET;Virgin HW 4th
通讯作者：
Virgin HW 4th
影响因子：
32.4
作者：
Liu, XQ;Dai, SD;Kappler, JW
通讯作者：
Kappler, JW
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
5.4
作者：
Afonso, CL;Tulman, ER;Kutish, GF
通讯作者：
Kutish, GF
影响因子：
5.6
作者：
Huang, QL;Petros, AM;Olejniczak, ET
通讯作者：
Olejniczak, ET