Chromogenic Cross-Linker for the Characterization of Protein Structure by Infrared Multiphoton Dissociation Mass Spectrometry
作者:Myles W. Gardner、Lisa A. Vasicek、Shagufta Shabbir、Eric V. Anslyn、Jennifer S. Brodbelt
DOI:10.1021/ac800625x
日期:2008.7.1
We have developed a new IR chromogenic cross-linker (IRCX) to aid in rapidly distinguishing cross-linked peptides from unmodified species in complex mixtures. By incorporating a phosphate functional group into the cross-linker, one can take advantage of its unique IR absorption properties, affording selective infrared multiphoton dissociation (IRMPD) of the cross-linked peptides. In a mock mixture of unmodified peptides and IRCX-cross-linked peptides (intramolecularly and intermolecularly cross-linked), only the peptides containing the IRCX modification were shown to dissociate upon exposure to 50 ms of 10.6-μm radiation. LC-IRMPD-MS proved to be an effective method to distinguish the cross-linked peptides in a tryptic digest of IRCX-cross-linked ubiquitin. A total of four intermolecular cross-links and two dead-end modifications were identified using IRCX and LC-IRMPD-MS. IRMPD of these cross-linked peptides resulted in secondary dissociation of all primary fragment ions containing the chromophore, producing a series of unmodified b- or y-type ions that allowed the cross-linked peptides to be sequenced without the need for collision-induced dissociation.
我们开发了一种新型红外显色交联剂 (IRCX),有助于快速区分复杂混合物中的交联肽和未修饰的肽。通过将磷酸盐官能团掺入交联剂中,人们可以利用其独特的红外吸收特性,提供交联肽的选择性红外多光子解离(IRMPD)。在未修饰肽和 IRCX 交联肽(分子内和分子间交联)的模拟混合物中,只有含有 IRCX 修饰的肽在暴露于 50 ms 的 10.6-μm 辐射时显示出解离。 LC-IRMPD-MS 被证明是区分 IRCX 交联泛素胰蛋白酶消化中交联肽的有效方法。使用IRCX 和LC-IRMPD-MS 总共鉴定了四个分子间交联和两个死端修饰。这些交联肽的 IRMPD 导致含有发色团的所有初级片段离子二次解离,产生一系列未修饰的 b 型或 y 型离子,从而无需碰撞诱导解离即可对交联肽进行测序。