Project description:In this project, we report the detrimental effect of hydroxylamine, a quenching reagent for NHS-amine reaction, on phosphopeptides. The degree of phosphopeptide enrichment was greatly improved by a desalting method compared with a vacuum-drying method right after quenching reaction. We demonstrate that vacuum-drying in presence of hydroxylamine promotes β-elimination of phosphate groups from phosphoserine and phosphothreonine.
Project description:ADH5 encodes for the protein GSNOR, an alchol dehydrogenase acting as a denitrosylase. GSNOR reduces S-nitrosoglutathione (GSNO) to an unstable intermediate, S-hydroxylaminoglutathione, which then rearranges to form glutathione sulfonamide, or in the presence of GSH, forms oxidized glutathione (GSSG) and hydroxylamine
Project description:Comparing the performance of methylamine and hydroxylamine on phospho-peptide analysis, particularly in relation to the identification of more complex dose-dependent patterns.
Project description:HeLa cells were lysed and free cysteines capped with iodoacetamide. S-acylation was hydrolysed with hydroxylamine and newly revealed Cys allowed to react with an alkyne-tagged probe. Proteins were clicked with azido-biotin, enriched on neutravidin beads, digested with trypsin and desalted.
Project description:HeLa cells were lysed and free cysteines were alkylated with the IAA-Bn light probe. S-acylation was hydrolysed with hydroxylamine and newly revealed Cys allowed to react with the IAA-Bn heavy probe. Proteins were clicked with AdadpsB, digested with trypsin, enriched on neutravidin beads and analysed by LC-MS/MS.
Project description:TET proteins oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). 5fC and 5caC are excised by mammalian DNA glycosylase TDG, implicating 5mC oxidation in DNA demethylation. Here we show that the genomic locations of 5fC can be determined by coupling chemical reduction with biotin tagging. Genome-wide mapping of 5fC in mouse embryonic stem cells (mESCs) reveals that 5fC preferentially occurs at poised enhancers among other gene regulatory elements. Application to Tdg null mESCs further suggests that 5fC production coordinates with p300 in remodeling epigenetic states of enhancers. This process, which is not influenced by 5hmC, appears to be associated with further oxidation of 5hmC and commitment to demethylation through 5fC. Finally, we resolved 5fC at base-resolution by hydroxylamine-based protection from bisulfite-mediated deamination, thereby confirming sites of 5fC accumulation. Our results reveal roles of active 5mC/5hmC oxidation and TDG-mediated demethylation in epigenetic tuning at regulatory elements.
Project description:<p> Elevated exposure to 4-hydroxyphenanthrenes (4-OHPhe) is positively associated with obesity risk. However, the specific pathogenic mechanism remains unclear. Here, we used SHapley Additive exPlanations (SHAP) and logistic regression analysis to identify a strong association between 4-OHPhe and obesity. Mechanistically, exposure to 4-OHPhe significantly downregulates the expression of hydroxylamine reductase (hcp) genes in Bacteroides uniformis (B. uniformis), thereby inhibiting the removal of reactive oxygen species (ROS) and reducing the abundance of B. uniformis. The decline in B. uniformis abundance reduces hyodeoxycholic acid (HDCA) production and consequent activation of the intestinal farnesoid X receptor (FXR)-ceramide pathway, which ultimately results in the downregulation of white adipose tissue (WAT) thermogenic genes and obesity. Both B. uniformis colonization and HDCA treatment were found to promote this thermogenic effect. These findings demonstrate that 4-OHPhe exacerbates obesity via impairment of gut microbiota composition, thereby establishing a mechanistic link between environmental toxins and host metabolism.</p>