Insights into catalysis and function of phosphoribosyl-linked serine ubiquitination.
Insights into catalysis and function of phosphoribosyl-linked serine ubiquitination.
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DOI：
10.1038/s41586-018-0145-8
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发表时间：
2018-05
期刊：
影响因子：
64.8
通讯作者：
Dikic I
中科院分区：
文献类型：
--
作者：
Kalayil S;Bhogaraju S;Bonn F;Shin D;Liu Y;Gan N;Basquin J;Grumati P;Luo ZQ;Dikic I
传统的泛素化通过催化底物蛋白中泛素（Ub）和伯胺之间形成ATP依赖的异肽键来调节关键的细胞过程。最近，致病性嗜肺军团菌的细菌效应蛋白SidE家族（SdeA、SdeB、SdeC和SidE）被证明利用NAD+介导宿主蛋白中丝氨酸残基的磷酸核糖基连接的泛素化（PR-泛素化）。然而，能够实现这种复杂的多步骤过程的催化平台的分子结构仍然未知。在这里，我们描述的结构组成的单-ADP-核糖基转移酶（MART）和磷酸二酯酶（PDE）结构域的SdeA的催化核心，并揭示了两个不同的催化位点丝氨酸泛素化的活性。mART催化位点由α-螺旋叶（阿勒）组成，与mART核心一起形成NAD+结合室和Ub的ADP-核糖基化室。PDE结构域中的催化位点将ADP-核糖基化Ub切割为磷酸核糖基Ub（PR-Ub），并介导两步PR-Ub转移反应：首先转移至催化性组氨酸277（形成瞬时SdeA：H277-PR-Ub中间体），随后转移至宿主蛋白中的丝氨酸残基。结构分析显示，底物结合裂缝的PDE结构域并列的催化位点，是必不可少的丝氨酸定位泛素化。使用简并底物肽和RTN 4 B中新鉴定的泛素化位点，我们表明，具有围绕目标丝氨酸残基的疏水残基的无序多肽是SdeA泛素化的优选底物。L.的感染研究。pneumophila表达SdeA的底物结合突变体的研究表明，底物泛素化而不是细胞Ub库的修饰决定了SdeA在急性细菌感染期间的病理生理作用。
Conventional ubiquitination regulates key cellular processes by catalyzing the ATP-dependent formation of an isopeptide bond between ubiquitin (Ub) and primary amines in substrate proteins. Recently, SidE family of bacterial effector proteins (SdeA, SdeB, SdeC and SidE) of pathogenic Legionella pneumophila were shown to utilize NAD+ to mediate phosphoribosyl-linked ubiquitination (PR-ubiquitination) of serine residues in host proteins. Yet, the molecular architecture of the catalytic platform enabling such a complex multistep process remained unknown. Here, we describe the structure of the catalytic core of SdeA composed of the mono-ADP-ribosyltransferase (mART) and the phosphodiesterase (PDE) domains and shed light on the activity of two distinct catalytic sites for serine ubiquitination. The mART catalytic site is composed of an α-helical lobe (AHL) that together with the mART-core creates a chamber for NAD+ binding and ADP-ribosylation of Ub. The catalytic site in the PDE domain cleaves ADP-ribosylated Ub to phosphoribosyl Ub (PR-Ub) and mediates a two-step PR-Ub transfer reaction: first to a catalytic histidine 277 (forming a transient SdeA:H277-PR-Ub intermediate) and subsequently to a serine residue in host proteins. Structural analysis revealed a substrate binding cleft in the PDE domain juxtaposing the catalytic site that is essential for serine positioning for ubiquitination. Using degenerate substrate peptides and newly identified ubiquitination sites in RTN4B, we show that disordered polypeptides with hydrophobic residues surrounding the target serine residues are preferred substrates for SdeA ubiquitination. Infection studies with L. pneumophila expressing substrate-binding mutants of SdeA revealed that substrate ubiquitination rather than modification of the cellular Ub pool determines the pathophysiological effect of SdeA during acute bacterial infection.
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影响因子：
30.3
作者：
Kotewicz KM;Ramabhadran V;Sjoblom N;Vogel JP;Haenssler E;Zhang M;Behringer J;Scheck RA;Isberg RR
通讯作者：
Isberg RR
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影响因子：
14.9
作者：
Nielsen M;Andreatta M
通讯作者：
Andreatta M
细菌效应物的泛素化不依赖于 E1 和 E2 酶。
影响因子：
64.8
作者：
Qiu J;Sheedlo MJ;Yu K;Tan Y;Nakayasu ES;Das C;Liu X;Luo ZQ
通讯作者：
Luo ZQ
影响因子：
3.4
作者：
Svergun, DI
通讯作者：
Svergun, DI
影响因子：
6.1
作者：
Kozin, MB;Svergun, DI
通讯作者：
Svergun, DI