SARS hCoV papain-like protease is a unique Lys48 linkage-specific di-distributive deubiquitinating enzyme.
SARS hCoV papain-like protease is a unique Lys48 linkage-specific di-distributive deubiquitinating enzyme.
复制标题
DOI：
10.1042/bj20141170
复制
发表时间：
2015-06-01
期刊：
影响因子：
--
通讯作者：
Huang TT
中科院分区：
文献类型：
--
作者：
Békés M;Rut W;Kasperkiewicz P;Mulder MP;Ovaa H;Drag M;Lima CD;Huang TT
泛素 (Ub) 和泛素样修饰剂干扰素刺激基因 15 (ISG15) 参与宿主对病毒感染的防御。病毒，包括严重急性呼吸系统综合症人类冠状病毒（SARS hCoV），为了自身优势而选择了 Ub/ISG15 缀合途径，或者进化出效应蛋白来对抗 Ub/ISG15 缀合宿主蛋白的促炎特性。在这里，我们比较了最近出现的中东呼吸综合征 (MERS) hCoV 中的木瓜蛋白酶 (PLpro) 与 SARS 中的相关蛋白酶 SARS PLpro 的底物特异性。通过生化检测，我们发现与 SARS PLpro 类似，MERS PLpro 既是一种去泛素化酶，也是一种去糖基化酶。对这些病毒蛋白酶的内在去泛素化酶 (DUB) 活性的进一步分析揭示了多聚泛素链的识别和切割特异性之间的独特差异。首先，MERS PLpro 对多聚泛素链的裂解表现出广泛的连锁特异性，而 SARS PLpro 更喜欢裂解 Lys48 连接的多聚泛素链。其次，MERS PLpro 以“单分配”方式（一次一个 Ub）切割多聚 Ub 链，而 SARS PLpro 更喜欢使用“双分配”切割机制，通过将 di-Ub 部分感知为最小识别元件来切割 K48 连接的多聚 Ub 链。 SARS PLpro 的双分配裂解机制在 USP 家族 DUB 中似乎并不常见，因为来自人类的相关 USP 家族成员不表现出这种机制。我们认为，SARS 和 MERS PLpro 之间的这些内在酶学差异将有助于识别这些病毒 DUB 的促炎底物，并可以指导设计抗击冠状病毒感染的疗法。
Ubiquitin (Ub) and the ubiquitin-like modifier interferon stimulated gene 15 (ISG15) participate in the host defense of viral infections. Viruses, including the Severe Acute Respiratory Syndrome human coronavirus (SARS hCoV), have co-opted Ub/ISG15-conjugation pathways for their own advantage or have evolved effector proteins to counter pro-inflammatory properties of Ub/ISG15-conjugated host proteins. Here, we compare substrate specificities of the papain-like protease (PLpro) from the recently emerged Middle Eastern Respiratory Syndrome (MERS) hCoV to the related protease from SARS, SARS PLpro. Through biochemical assays, we show that similar to SARS PLpro, MERS PLpro is both a deubiquitinating and a deISGylating enzyme. Further analysis of the intrinsic deubiquitinating enzyme (DUB) activity of these viral proteases revealed unique differences between the recognition and cleavage specificities of polyUb chains. First, MERS PLpro shows broad linkage specificity for the cleavage of polyUb chains, while SARS PLpro prefers to cleave Lys48-linked polyUb chains. Second, MERS PLpro cleaves polyUb chains in a “mono-distributive” manner (one Ub at a time), and SARS PLpro prefers to cleave K48-linked poly-Ub chains by sensing a di-Ub moiety as a minimal recognition element using a “di-distributive” cleavage mechanism. The di-distributive cleavage mechanism for SARS PLpro appears to be uncommon among USP-family DUBs, as related USP family members from humans do not display such a mechanism. We propose that these intrinsic enzymatic differences between SARS and MERS PLpro will help identify pro-inflammatory substrates of these viral DUBs and can guide in the design of therapeutics to combat infection by coronaviruses.