Sun Hao, Meledin Roman, Mali Sachitanand M, Brik Ashraf
Schulich Faculty of Chemistry , Technion Israel Institute of Technology , Haifa , 3200008 , Israel . Email:
Chem Sci. 2018 Jan 11;9(6):1661-1665. doi: 10.1039/c7sc04518b. eCollection 2018 Feb 14.
Ester-linked ubiquitinated proteins have been reported by several groups to be involved in ubiquitin signalling. However, due to the lack of the suitable tools to homogeneously produce such conjugates, their exact physiological roles and biochemical behavior remain enigmatic. Here, we report for the first time on the development of a novel synthetic strategy based on total chemical synthesis of proteins to construct ubiquitinated proteins, where ubiquitin is linked to the substrate an ester bond. In this study, we prepared ester- and isopeptide-linked ubiquitinated α-globin and examined their relative behaviors with various deubiquitinases. We found that deubiquitinases are able to cleave the ester linkage with different efficiency relative to the isopeptide-linked substrate. These results may indicate that ester-linked ubiquitinated proteins are natural substrates for deubiquitinases.
几个研究小组都报道了酯连接的泛素化蛋白参与泛素信号传导。然而，由于缺乏合适的工具来均匀地产生此类缀合物，它们的确切生理作用和生化行为仍然是个谜。在这里，我们首次报道了一种基于蛋白质全化学合成构建泛素化蛋白的新型合成策略，其中泛素通过酯键与底物相连。在本研究中，我们制备了酯连接和异肽连接的泛素化α-珠蛋白，并研究了它们与各种去泛素化酶的相对作用。我们发现，相对于异肽连接的底物，去泛素化酶能够以不同的效率切割酯键。这些结果可能表明酯连接的泛素化蛋白是去泛素化酶的天然底物。
