Exploring Spacer Arm Structures for Designs of Asymmetric Sulfoxide-Containing MS-Cleavable Cross-Linkers
Year: 2020
Type: article
Abstract: Cross-linking mass spectrometry (XL-MS) has become a powerful structural tool for defining protein–protein interactions (PPIs) and elucidating architectures of large protein assemblies. To advance XL-MS studies, we have previously developed a series of sulfoxide-containing MS-cleavable cross-linkers to facilitate the detection and identification of cross-linked peptides using multistage mass spectrometry (MS n ). While current sulfoxide-based cross-linkers are effective for in vivo and in vitro XL-MS studies at the systems-level, new reagents are still needed to help expand PPI coverage. To this end, we have designed and synthesized six variable-length derivatives of disuccinimidyl sulfoxide (DSSO) to better understand the effects of spacer arm modulation on MS-cleavability, fragmentation characteristics, and MS identification of cross-linked peptides. In addition, the impact on cross-linking reactivity was evaluated. Moreover, alternative MS 2 -based workflows were explored to determine their feasibility for analyzing new sulfoxide-containing cross-linked products. Based on the results of synthetic peptides and a model protein, we have further demonstrated the robustness and predictability of sulfoxide chemistry in designing MS-cleavable cross-linkers. Importantly, we have identified a unique asymmetric design that exhibits preferential fragmentation of cross-links over peptide backbones, a desired feature for MS n analysis. This work has established a solid foundation for further development of sulfoxide-containing MS-cleavable cross-linkers with new functionalities.
Source: Analytical Chemistry
Institution: University of California, Irvine
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3012925536