Faculty of Physics, University of Vienna, VCQ, Boltzmanngasse 5, A-1090 Vienna, Austria.
Phys Chem Chem Phys. 2018 Apr 25;20(16):11412-11417. doi: 10.1039/c8cp01058g.
Photocleavable tags (PCTs) have the potential for excellent spatio-temporal control over the release of subunits of complex molecules. Here, we show that electrosprayed oligopeptides, functionalized by a tailored ortho-nitroarylether can undergo site-specific photo-activated cleavage under UV irradiation (266 nm) in high vacuum. The comparison of UV photodissociation (UVPD) and collision-induced dissociation (CID) points to the thermal nature of the cleavage mechanism, a picture corroborated by the temperature dependence of the process. Two competing photodissociation pathways can be identified. In one case a phenolate anion is separated from a neutral zwitterion. In the other case a neutral phenol derivative leaves a negatively charged peptide behind. To understand the factors favoring one channel over the other, we investigate the influence of the peptide length, the nature of the phenolic group and the position of the nitro-group (ortho vs. para). The observed gas phase cleavage of a para-nitro benzylic ether markedly differs from the established behavior in solution.
光解标签（PCTs）在控制复杂分子亚基的释放方面具有出色的时空特异性。在这里，我们展示了经定制的邻硝基芳基醚官能化的电喷雾寡肽可以在高真空下，在 266nm 的紫外光照射下进行特异性光激活裂解。紫外光解（UVPD）和碰撞诱导解离（CID）的比较指出了裂解机制的热性质，这一图像得到了该过程温度依赖性的证实。可以识别两种竞争的光解途径。一种情况下，酚盐阴离子从中性两性离子中分离出来。另一种情况下，中性苯酚衍生物留下带负电荷的肽。为了了解哪种途径占优势的因素，我们研究了肽长度、酚基团的性质以及硝基位置（邻位与对位）的影响。观察到的对位硝基苄醚的气相裂解明显不同于在溶液中已建立的行为。
