Zou Kun, Yang Jinyu, Gao Yingxiao, Feng Feng, Wu Mingxuan
Department of Chemistry, Zhejiang University 310027 Hangzhou Zhejiang Province China
Department of Chemistry, School of Science, Westlake University 310030 Hangzhou Zhejiang Province China.
Chem Sci. 2024 Dec 12;16(4):1849-1856. doi: 10.1039/d4sc05886k. eCollection 2025 Jan 22.
Sulfonium is an electrophilic and biocompatible group that is widely applied in synthetic chemistry on small molecules. However, there have been few developments of peptide or protein-based sulfonium tools. We recently reported sulfonium-mediated tryptophan crosslinking and developed NleSme2 (norleucine-dimethylsulfonium) peptides as dimethyllysine mimics that crosslink site-specific methyllysine readers. Therefore, sulfonium probes show great potential for investigating methyllysine readers and other aromatic cage-containing proteins. However, the current synthesis is not very efficient and is limited to peptide probes that, in many cases, cannot mimic protein-protein interactions. In addition to peptidyl conjugates that are valuable for reader identification, there are unavoidable methyl conjugates as side products. As a result, a robust method to prepare peptide and protein sulfonium tools with great crosslinking reactivity and selectivity is highly desirable. Here, we report a cysteine alkylation method to introduce site-specific sulfonium at protein level with excellent yield. In addition to dimethylsulfonium, we also developed cyclic sulfonium warheads that enhanced peptidyl conjugate selectivity. The method thus made it possible to prepare nucleosome probes in which LEDGF and NSD2, as H3K36 methylation readers were readily crosslinked. We thus believe this method will accelerate the development of sulfonium peptide and protein tool sets for broad applications in chemical biology studies.
锍是一种亲电且具有生物相容性的基团，广泛应用于小分子的合成化学中。然而，基于肽或蛋白质的锍工具的开发却很少。我们最近报道了锍介导的色氨酸交联，并开发了NleSme2（正亮氨酸 - 二甲基锍）肽作为二甲基赖氨酸模拟物，可交联位点特异性甲基赖氨酸识别蛋白。因此，锍探针在研究甲基赖氨酸识别蛋白和其他含芳香笼的蛋白质方面具有巨大潜力。然而，目前的合成效率不高，并且仅限于肽探针，在许多情况下，这些肽探针无法模拟蛋白质 - 蛋白质相互作用。除了对识别蛋白有价值的肽基缀合物外，不可避免地会产生甲基缀合物作为副产物。因此，非常需要一种强大的方法来制备具有高交联反应性和选择性的肽和蛋白质锍工具。在这里，我们报告了一种半胱氨酸烷基化方法，可在蛋白质水平上以优异的产率引入位点特异性锍。除了二甲基锍之外，我们还开发了环状锍弹头，增强了肽基缀合物的选择性。该方法因此使得制备核小体探针成为可能，其中作为H3K36甲基化识别蛋白的LEDGF和NSD2很容易交联。因此，我们相信这种方法将加速锍肽和蛋白质工具集的开发，以便在化学生物学研究中广泛应用。
