The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
Nat Nanotechnol. 2014 Oct;9(10):835-40. doi: 10.1038/nnano.2014.193. Epub 2014 Sep 14.
Post-translational modifications alter the properties of proteins through the cleavage of peptide bonds or the addition of a modifying group to one or more amino acids. These modifications allow proteins to perform their primary biological functions, but single-protein studies of post-translational modifications have been hindered by a lack of suitable analysis methods. Here, we show that single amino acids can be identified using electron tunnelling currents measured as the individual molecules pass through a nanoscale gap between electrodes. We identify 12 different amino acids and the post-translational modification phosphotyrosine, which is involved in the process that switches enzymes on and off. Furthermore, we show that the conductance measurements can be used to partially sequence peptides of an epidermal growth factor receptor substrate, and can discriminate a peptide from its phosphorylated variant.
翻译后修饰通过切割肽键或向一个或多个氨基酸添加修饰基团来改变蛋白质的性质。这些修饰使蛋白质能够执行其主要的生物学功能，但由于缺乏合适的分析方法，对翻译后修饰的单一蛋白质研究受到了阻碍。在这里，我们表明，单个氨基酸可以通过测量单个分子通过电极之间的纳米级间隙时的电子隧道电流来识别。我们鉴定出 12 种不同的氨基酸和翻译后修饰磷酸酪氨酸，它参与了酶的开启和关闭过程。此外，我们还表明，电导测量可用于部分测序表皮生长因子受体底物的肽，并可区分肽与其磷酸化变体。
