Acyl modifications vary greatly in terms of elemental composition and site of protein modification. Developing methods to identify acyl modifications more confidently can help to assess the scope of these modifications in large proteomic datasets. The utility of acyl‐lysine immonium ions is analyzed for identifying the modifications in proteomic datasets. It is demonstrated that the cyclized immonium ion is a strong indicator of acyl‐lysine presence when its rank or relative abundance compared to other ions within a spectrum is considered. Utilizing a stepped collision energy method in a shotgun experiment highlights the immonium ion. By implementing an analysis that accounted for features within each MS² spectrum, the method clearly identifies peptides with short chain acyl‐lysine modifications from complex lysates. Immonium ions can also be used to validate novel acyl modifications; in this study, the first examples of 3‐hydroxylpimelyl‐lysine modifications are reported and they are validated using immonium ions. Overall these results solidify the use of the immonium ion as a marker for acyl‐lysine modifications in complex proteomic datasets.

中文翻译：

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利用亚铵离子靶向蛋白质组数据集中的酰基赖氨酸修饰


酰基修饰在元素组成和蛋白质修饰位点方面差异很大。开发更自信地识别酰基修饰的方法有助于评估大型蛋白质组数据集中这些修饰的范围。分析酰基赖氨酸铵离子的效用，以识别蛋白质组数据集中的修饰。事实证明，当考虑与光谱内其他离子相比的等级或相对丰度时，环化亚铵离子是酰基赖氨酸存在的有力指示剂。在鸟枪实验中使用阶梯式碰撞能量法突出显示了亚铵离子。通过对每个 MS ²谱图内的特征进行分析，该方法可以从复杂的裂解物中清楚地识别出具有短链酰基赖氨酸修饰的肽。亚铵离子也可用于验证新型酰基修饰；在这项研究中，报道了 3-羟基庚二酰-赖氨酸修饰的第一个例子，并使用亚铵离子对其进行了验证。总的来说，这些结果巩固了亚铵离子作为复杂蛋白质组数据集中酰基赖氨酸修饰标记的用途。