title: A Chemical Approach for the Detection of Protein Sulfinylation.
abstract: Protein sulfinic acids are formed by the reaction of reactive oxygen species with protein thiols. Sulfinic acid formation has long been considered an irreversible state of oxidation and is associated with high cellular oxidative stress. Increasing evidence, however, indicates that cysteine is oxidized to sulfinic acid in cells to a greater extent, and is more controlled, than first thought. The discovery of sulfiredoxin has demonstrated that cysteine sulfinic acid can be reversed, pointing to a vast array of potential implications for redox biology. Identification of the site of protein sulfinylation is crucial in clarifying the physiological and pathological effects of post-translational modifications. Currently, the only methods for detection of sulfinic acids involve mass spectroscopy and the use of specific antibodies. However, these methodologies are not suitable for proteomic studies. Herein, we report the first probe for detection of protein sulfinylation, NO-Bio, which combines a C-nitroso warhead for rapid labeling of sulfinic acid with a biotin handle. Based on this new tool, we developed a selective two-step approach. In the first, a sulfhydryl-reactive compound is introduced to selectively block free cysteine residues. Thereafter, the sample is treated with NO-Bio to label sulfinic acids. This new technology represents a rapid, selective, and general technology for sulfinic acid detection in biological samples. As proof of our concept, we also evaluated protein sulfinylation levels in various human lung tumor tissue lysates. Our preliminary results suggest that cancer tissues generally have higher levels of sulfinylation in comparison to matched normal tissues. A new ability to monitor protein sulfinylation directly should greatly expand the impact of sulfinic acid as a post-translational modification.
authors.affiliation: †Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, United States.
authors.forename: Mauro
authors.initials: M
authors.lastname: Lo Conte
authors.affiliation: ‡Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588, United States.
authors.forename: Jiusheng
authors.initials: J
authors.lastname: Lin
authors.affiliation: ‡Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588, United States.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wilson
authors.affiliation: †Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, United States.
authors.forename: Kate S
authors.initials: KS
authors.lastname: Carroll
mesh_terms: D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007202:Indicators and Reagents / Q000737:chemistry; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology; D009603:Nitroso Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D040901:Proteomics; D013194:Staining and Labeling; D013441:Sulfinic Acids / Q000032:analysis* / Q000378:metabolism
chemical_list: D007202:Indicators and Reagents; D009603:Nitroso Compounds; D011506:Proteins; D013441:Sulfinic Acids; D003545:Cysteine