Light-driven post-translational installation of reactive protein side chains
Light-driven post-translational installation of reactive protein side chains
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DOI：
10.1038/s41586-020-2733-7
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发表时间：
2020-09-24
期刊：
影响因子：
64.8
通讯作者：
Davis, Benjamin G.
中科院分区：
文献类型：
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作者：
Josephson, Brian;Fehl, Charlie;Davis, Benjamin G.
通过添加光生成的烷基或二氟烷基自由基，各种侧链被安装到蛋白质中，为蛋白质提供了新的功能和反应性。翻译后修饰（PTMs）极大地扩展了蛋白质的结构和功能（1,2）。尽管合成蛋白质功能化策略允许模仿ptms3,4，以及形成具有多种潜在功能的非自然蛋白质变体，包括药物携带(5)、跟踪、成像(6)和伴侣交联(7)，但可以引入的功能基团范围仍然有限。在这里，我们描述了通过形成以碳为中心的自由基，在水中形成C-C键，在蛋白质中脱氢丙氨酸残基的可见光驱动侧链的安装。控制反应氧化还原允许位点选择性修饰，具有良好的转化和减少蛋白质损伤。硼酸儿茶酚酯衍生物原位生成RH(2)C（中心点）自由基，形成天然残基和PTMs的天然（β - ch2 - γ - ch2）键，而吡啶基磺酰基衍生物原位增强Fe（ii）生成RF(2)C（中心点）自由基，形成等效的带有二氟乙烯标签的β - ch2 - γ - cf(2)键。这些反应具有化学耐受性，并将广泛的功能（超过50个独特的残基/侧链）整合到不同的蛋白质支架和位点中。在自由基前体中存在敏感基团的情况下，可以选择性地进行起始反应，使以前不相容的侧链得以安装。所得蛋白的功能和反应性用于安装自由基前体，用于蛋白上的均溶自由基生成；通过同时检测化学选择性和立体选择性，研究天然、非天然和cf2标记的翻译后修饰蛋白底物的酶功能；并创造具有异解共价键形成活性谱的通用“烷基化蛋白”（即，在一个极端与小分子发生不同反应，或通过良好的模仿选择性地与蛋白质目标发生反应）。翻译后对这些反应和蛋白质上的化学基团的访问对于揭示和创造蛋白质功能都是有用的。
A wide range of side chains are installed into proteins by addition of photogenerated alkyl or difluroalkyl radicals, providing access to new functionality and reactivity in proteins.Post-translational modifications (PTMs) greatly expand the structures and functions of proteins in nature(1,2). Although synthetic protein functionalization strategies allow mimicry of PTMs3,4, as well as formation of unnatural protein variants with diverse potential functions, including drug carrying(5), tracking, imaging(6)and partner crosslinking(7), the range of functional groups that can be introduced remains limited. Here we describe the visible-light-driven installation of side chains at dehydroalanine residues in proteins through the formation of carbon-centred radicals that allow C-C bond formation in water. Control of the reaction redox allows site-selective modification with good conversions and reduced protein damage. In situ generation of boronic acid catechol ester derivatives generates RH(2)C(center dot)radicals that form the native (beta-CH2-gamma-CH2) linkage of natural residues and PTMs, whereas in situ potentiation of pyridylsulfonyl derivatives by Fe(ii) generates RF(2)C(center dot)radicals that form equivalent beta-CH2-gamma-CF(2)linkages bearing difluoromethylene labels. These reactions are chemically tolerant and incorporate a wide range of functionalities (more than 50 unique residues/side chains) into diverse protein scaffolds and sites. Initiation can be applied chemoselectively in the presence of sensitive groups in the radical precursors, enabling installation of previously incompatible side chains. The resulting protein function and reactivity are used to install radical precursors for homolytic on-protein radical generation; to study enzyme function with natural, unnatural and CF2-labelled post-translationally modified protein substrates via simultaneous sensing of both chemo- and stereoselectivity; and to create generalized 'alkylator proteins' with a spectrum of heterolytic covalent-bond-forming activity (that is, reacting diversely with small molecules at one extreme or selectively with protein targets through good mimicry at the other). Post-translational access to such reactions and chemical groups on proteins could be useful in both revealing and creating protein function.