Substrate profiling of PRMT1 reveals amino acid sequences that extend beyond the "RGG" paradigm.
Substrate profiling of PRMT1 reveals amino acid sequences that extend beyond the "RGG" paradigm.
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DOI：
10.1021/bi800984s
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发表时间：
2008-08
期刊：
影响因子：
2.9
通讯作者：
W. Wooderchak;T. Zang;Z. Zhou;Marcela Acuña;S. Tahara;J. Hevel
中科院分区：
文献类型：
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作者：
W. Wooderchak;T. Zang;Z. Zhou;Marcela Acuña;S. Tahara;J. Hevel
蛋白质精氨酸甲基转移酶1（PRMT 1）催化某些蛋白质精氨酸残基的单-和二甲基化。虽然这种翻译后修饰已被牵连在许多生理过程中，PRMT 1底物识别的分子基础知之甚少。已知PRMT 1底物中的大多数修饰的精氨酸残基位于重复的“RGG”序列中。然而，PRMT 1也特异性甲基化组蛋白H4的Arg 3在一个区域，这是不是甘氨酸精氨酸丰富，表明PRMT 1底物不限于蛋白质轴承“RGG”序列。由于尚未对PRMT 1底物特异性进行系统评价，因此尚不清楚“RGG”序列是否准确代表PRMT 1的共有靶标。使用基于源自体内底物原纤蛋白的序列的聚焦肽文库，我们观察到PRMT 1甲基化了在“RX（1）”和“RX（1）X（2）”位置具有除甘氨酸以外的氨基酸残基的底物。重要的是，鉴定了11个额外的PRMT 1底物序列。我们的结果还说明，在N-末端侧的修饰位点的两个残基是重要的，不需要都是甘氨酸。PRMT 1甲基化真核起始因子4A 1（eIF 4A 1）蛋白，其具有单个“RGG”序列。eIF 4A 1和类似的eIF 4A 3的甲基化可以使用邻近修饰位点的单位点突变来影响，这证明了氨基酸序列在PRMT 1蛋白底物中的重要性。亲本文库肽的二甲基化显示通过解离机制发生。总之，PRMT 1选择性地识别底物中延伸超出“RGG”范例的一组氨基酸序列。
Protein arginine methyltransferase 1 (PRMT1) catalyzes the mono- and dimethylation of certain protein arginine residues. Although this posttranslational modification has been implicated in many physiological processes, the molecular basis for PRMT1 substrate recognition is poorly understood. Most modified arginine residues in known PRMT1 substrates reside in repeating "RGG" sequences. However, PRMT1 also specifically methylates Arg3 of histone H4 in a region that is not glycine-arginine rich, suggesting that PRMT1 substrates are not limited to proteins bearing "RGG" sequences. Because a systematic evaluation of PRMT1 substrate specificity has not been performed, it is unclear if the "RGG" sequence accurately represents the consensus target for PRMT1. Using a focused peptide library based on a sequence derived from the in vivo substrate fibrillarin we observed that PRMT1 methylated substrates that had amino acid residues other than glycine in the "RX (1)" and "RX (1)X (2)" positions. Importantly, eleven additional PRMT1 substrate sequences were identified. Our results also illustrate that the two residues on the N-terminal side of the modification site are important and need not both be glycine. PRMT1 methylated the eukaryotic initiation factor 4A1 (eIF4A1) protein, which has a single "RGG" sequence. Methylation of eIF4A1 and the similar eIF4A3 could be affected using single site mutations adjacent to the modification site, demonstrating the importance of amino acid sequence in PRMT1 protein substrates. Dimethylation of the parent library peptide was shown to occur through a dissociative mechanism. In summary, PRMT1 selectively recognizes a set of amino acid sequences in substrates that extend beyond the "RGG" paradigm.