Se-Adenosyl-l-selenomethionine Cofactor Analogue as a Reporter of Protein Methylation

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• 作者：Ian R. Bothwell ; Kabirul Islam ; Yuling Chen ; Weihong Zheng ; Gil Blum ; Haiteng Deng ; Minkui Luo
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：September 12, 2012
• 年：2012
• 卷：134
• 期：36
• 页码：14905-14912
• 全文大小：417K
• 年卷期：v.134,no.36(September 12, 2012)
• ISSN：1520-5126

文摘

Posttranslational methylation by S-adenosyl-l-methionine(SAM)-dependent methyltransferases plays essential roles in modulating protein function in both normal and disease states. As such, there is a growing need to develop chemical reporters to examine the physiological and pathological roles of protein methyltransferases. Several sterically bulky SAM analogues have previously been used to label substrates of specific protein methyltransferases. However, broad application of these compounds has been limited by their general incompatibility with native enzymes. Here we report a SAM surrogate, ProSeAM (propargylic Se-adenosyl-l-selenomethionine), as a reporter of methyltransferases. ProSeAM can be processed by multiple protein methyltransferases for substrate labeling. In contrast, sulfur-based propargylic SAM undergoes rapid decomposition at physiological pH, likely via an allene intermediate. In conjunction with fluorescent/affinity-based azide probes, copper-catalyzed azide鈥揳lkyne cycloaddition chemistry, in-gel fluorescence visualization and proteomic analysis, we further demonstrated ProSeAM鈥檚 utility to profile substrates of endogenous methyltransferases in diverse cellular contexts. These results thus feature ProSeAM as a convenient probe to study the activities of endogenous protein methyltransferases.