A solid-phase compatible silane-based cleavable linker enables custom isobaric quantitative chemoproteomics
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Orbitrap Eclipse
ORGANISM(S): Homo Sapiens (human)
SUBMITTER: 
Nik Burton
LAB HEAD: Keriann Marie Backus
PROVIDER: PXD040737 | Pride | 2023-09-20
REPOSITORIES: Pride
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Project description:Only ~4% of the human proteome has been drugged by FDA approved molecules. Consequently, closing this druggability gap is a central focus of mass spectrometry chemoproteomics screening platforms. Despite increasingly widespread adoption, established chemoproteomic platforms fall short of achieving comprehensive proteome-wide structure activity relationship (SAR) maps for two key reasons: (1) time consuming and cumbersome sample preparation workflows and (2) and low throughput sample acquisition. Here we report the silane-based Cleavable Linkers for Isotopically-labeled Proteomics (sCLIP) method. sCLIP streamlines sample preparation with unparalleled early-stage isobaric labeling and sample pooling, allowing for increased sample throughput via customized low cost 6-plex sample multiplexing. The sCLIP method is distinguished by its unprecedented click-assembled isobaric tags, in which the reporter group is encoded in the sCLIP capture reagent and balancer in the pan cysteine-reactive probe. When paired with a custom FragPipe data analysis workflow and applied to cysteine-reactive fragment screens, sCLIP proteomics revealed established and unprecedented cysteine-ligand pairs, including those labeled by covalent-reversible electrophilic modalities.
2023-09-20 | PXD040696 | Pride
Project description:We report here a Cu-catalyzed azide-alkyne-thiol reaction forming thiotriazoles as the major by-product under widely used bioorthogonal protein labelling “click” conditions. The development of Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) had tremendous impact on many biological discoveries. However, the considered chemoselectivity of CuAAC is hampered by high reactivity of cysteine free thiols yielding thiotriazole protein conjugates. The reaction by-products generate false positive protein hits in “functional” proteomic studies. The reported detail investigation of conjugates between chemical probes containing terminal alkynes, azide-tags and cell lysates reveals formation of thiotriazoles, which can be readily detected by in-gel fluorescence scanning or after peptide and protein enrichment by MS-based proteomics. The produced fluorescent bands or enriched proteins may not result from the important enzymatically driven reaction and can be falsely assigned as hits. This study provides a complete list of the most common background proteins. The knowledge of this previously overlooked reactivity now leads to improved experimental design. Here, we present modified CuAAC conditions, which avoids the undesired product formation and diminishes the background.
2024-01-12 | PXD043402 | Pride
Project description:Higher-energy C-trap dissociation (HCD) of triazole-and biotin-modified peptides affords several characteristic fragment ions, including previously reported and newly identified species. Using the open and mass offset search strategies, we conduct an in-depth analysis of the relative intensities and specificity of these signature fragments. Through comparison of structurally matched isotopologues, we pinpoint the nature of the observed fragments.By varying the nature of the labeling reagent, including linker length, number of fragmentable bonds, and position of the triazole, we also achieve improved coverage of labeled peptides. The combination of labile and non-labile ion searches also affords an improvement in the chemoproteomic detected (CpD) cysteines identified. Collectively our study demonstrates the utility of labile ion and mass offset search strategies in the analysis of chemoproteomics datasets and reveals the ubiquity of triazole fragmentation in MS/MS analysis of chemically modified peptides.
2021-11-03 | PXD028853 | Pride
Project description:Higher-energy C-trap dissociation (HCD) of triazole-and biotin-modified peptides affords several characteristic fragment ions, including previously reported and newly identified species. Using the open and mass offset search strategies, we conduct an in-depth analysis of the relative intensities and specificity of these signature fragments. Through comparison of structurally matched isotopologues, we pinpoint the nature of the observed fragments.By varying the nature of the labeling reagent, including linker length, number of fragmentable bonds, and position of the triazole, we also achieve improved coverage of labeled peptides. The combination of labile and non-labile ion searches also affords an improvement in the chemoproteomic detected (CpD) cysteines identified. Collectively our study demonstrates the utility of labile ion and mass offset search strategies in the analysis of chemoproteomics datasets and reveals the ubiquity of triazole fragmentation in MS/MS analysis of chemically modified peptides.
2022-07-22 | PXD030737 | Pride
Project description:To cause disease, Salmonella enterica serovar Typhimurium requires two type-III secretion systems, encoded on Salmonella Pathogenicity Islands 1 and 2 (SPI-1 and -2). These secretion systems serve to deliver virulence proteins, termed effectors, into the host cell cytosol. While the importance of these effector proteins to promote colonization and replication within the host has been established, the specific roles of individual secreted effectors in the disease process are not well understood. In this study, we used an in vivo gallbladder epithelial cell infection model to study the function of the SPI-2-encoded effector, SseL. Deletion of the sseL gene resulted in bacterial filamentation and elongation and unusual localization of Salmonella within infected epithelial cells. Infection with the ?sseL strain also caused dramatic changes in lipid metabolism and led to massive accumulation of lipid droplets in infected cells. Some of these changes were investigated through metabolomics of gallbladder tissue. This phenotype was directly attributed to the deubiquitinase activity of SseL, as a Salmonella strain carrying a single point mutation in the catalytic cysteine resulted in the same phenotype as the deletion mutant. Excessive buildup of lipids due to the absence of a functional sseL gene was also observed in S. Typhimurium-infected livers. These results demonstrate that SseL alters host lipid metabolism in infected epithelial cells by modifying ubiquitination patterns of cellular targets. Female C57BL/6 mice were infected with the indicated strain of Salmonella enterica serovar Typhimurium by oral gavage. Four gallbladders were collected and pooled per sample group and metabolites extracted using a mixture of methanol and chloroform. Extracts were infused into a 12-T Apex-Qe hybrid quadrupole-FT-ICR mass spectrometer equipped with an Apollo II electrospray ionization source, a quadrupole mass filter and a hexapole collision cell. Raw mass spectrometry data were processed as described elsewhere (Han et al. 2008. Metabolomics. 4:128-140). To identify differences in metabolite composition between different groups of samples, we filtered the list of masses for metabolites which were present on one set of samples but not the other. Additionally, we calculated the ratios between averaged intensities of metabolites from each group of mice. To assign possible metabolite identities, monoisotopic neutral masses of interest were queried against MassTrix (http://masstrix.org). Masses were searched against the Mus musculus database within a mass error of 3 ppm.
2011-08-22 | E-GEOD-27604 | biostudies-arrayexpress
Project description:Cysteine residues undergo various oxidative modifications, acting as key sensors of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Given that ROS and RNS have known roles in many pathophysiological processes, numerous proteome-wide strategies to profile cysteine oxidation state have emerged in the last decade. Recent advancements to traditional redox profiling methods include incorporation of costly isotopic labeling reagents to allow for more quantitative assessment of oxidation states. These methods are typically carried out by using sequential thiol capping and reduction steps in order to label redox-sensitive cysteines, often found in di-cysteine motifs (‘CXXC’ or ‘CXXXC’). Tailored, pricy algorithms are commonly used to analyze redox-profiling datasets, the majority of which cannot accurately quantify site-of-labeling in redox-motifs; moreover, accurate quantification is confounded by excess labeling reagents during sample preparation. Here, we present a low-cost redox-profiling workflow using newly synthesized isotopic reagents compatible with SP3-bead technology, termed SP3-ROx, that allows for high throughput, rapid identification of redox-sensitive cysteines. We optimize cysteine labeling quantification using the FragPipe suite, an open source GUI for MSfragger-based search algorithm. Application of SP3-ROx to naive and activated T cells identifies redox-senstive cysteines, showcasing the utility of this workflow to study biological processes.
2022-03-02 | PXD029500 | Pride
Project description:Cysteine residues undergo various oxidative modifications, acting as key sensors of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Given that ROS and RNS have known roles in many pathophysiological processes, numerous proteome-wide strategies to profile cysteine oxidation state have emerged in the last decade. Recent advancements to traditional redox profiling methods include incorporation of costly isotopic labeling reagents to allow for more quantitative assessment of oxidation states. These methods are typically carried out by using sequential thiol capping and reduction steps in order to label redox-sensitive cysteines, often found in di-cysteine motifs (‘CXXC’ or ‘CXXXC’). Tailored, pricy algorithms are commonly used to analyze redox-profiling datasets, the majority of which cannot accurately quantify site-of-labeling in redox-motifs; moreover, accurate quantification is confounded by excess labeling reagents during sample preparation. Here, we present a low-cost redox-profiling workflow using newly synthesized isotopic reagents compatible with SP3-bead technology, termed SP3-ROx, that allows for high throughput, rapid identification of redox-sensitive cysteines. We optimize cysteine labeling quantification using the FragPipe suite, an open source GUI for MSfragger-based search algorithm. Application of SP3-ROx to naive and activated T cells identifies redox-senstive cysteines, showcasing the utility of this workflow to study biological processes.
2022-03-02 | PXD031647 | Pride
Project description:Effects to protein homeostasis processes upon treatment with cysteine-reactive covalent small molecules in viral and host proteins
2024-10-24 | PXD046393 | Pride
Project description:The importance of the mammalian intestinal microbiota to human health has been intensely studied over the past few years. It is now clear that the interactions between human hosts and their associated microbial communities need to be characterized in molecular detail if we are to truly understand human physiology. Additionally, the study of such host-microbe interactions is likely to provide us with new strategies to manipulate such complex systems to maintain or restore homeostasis in order to prevent or cure pathological states. We describe the use of high-throughput metabolomics to shed light on the interactions between the intestinal microbiota and the host. We show that treatment with the antibiotic streptomycin disrupts intestinal homeostasis and has a profound impact on the intestinal metabolome, affecting the levels of over 87% of all metabolites detected. Many metabolic pathways that are critical for host physiology were affected, including bile acid, eicosanoid and steroid hormone synthesis. Interestingly, many of these pathways are also affected by intestinal pathogens. Dissecting the effect of both beneficial and pathogenic bacteria on some of these pathways will be instrumental in understanding the interplay between the host, the resident microbiota and incoming pathogens and may aid in the design of new therapeutic strategies that target these interactions. Age-matched female C57BL/6 mice were used. Fresh feces were collected and stored at -80 oC. Mice were then treated with 20 mg of streptomycin through oral gavage and fresh feces were collected 24 hours after treatment and stored at -80 oC until used. To extract metabolites from feces, acetonitrile was added to samples (approximately 10-25 μL of acetonitrile per 1 mg of tissue), which were then homogenized. The samples were then cleared by centrifugation and the supernatant was collected and dried at room temperature using a centrifuge equipped with a vacuum pump. All extracts were kept at -80 oC until used. For metabolic profiling, the dried extracts from mouse feces were suspended in a 2:3 mixture of water and acetonitrile (10 μL per 1 mg of tissue), vortexed and cleared by centrifugation. Supernatants were collected and used as described below. Extracts were diluted 1:5 with 60% acetonitrile containing either 0.2% formic acid (for positive ion mode) or 0.5% ammonium hydroxide (for negative ion mode) and spiked with predefined amounts of the "ES tuning mix" solution as the internal standard for mass calibration. The solutions were then infused, using a syringe pump (KDS Scientific, Holliston, USA) at a flow rate of 2.5 µL per minute, into a 12-T Apex-Qe hybrid quadrupole-FT-ICR mass spectrometer (Bruker Daltonics, Billerica, USA) equipped with an Apollo II electrospray ionization source, a quadrupole mass filter and a hexapole collision cell. Data were recorded in positive and negative ion modes with broadband detection and an FT acquisition size of 1024 kilobytes per second, within a range of m/z 150 to 1100. Under these settings, a mass resolution of ca. 100,000 (full width at half maximum, FWHM) at m/z 400 and a mass accuracy within 2 ppm or less for all detected components, following internal mass calibration, were observed. Other experimental parameters were: capillary electrospray voltage of 3600-3750 V, spray shield voltage of 3300-3450 V, source ion accumulation time of 0.1 s and collision cell ion accumulation time of 0.2 s. To increase detection sensitivity, survey scan mass spectra in positive and negative ion modes were acquired from the accumulation of 200 scans per spectrum, and duplicate acquisitions per sample were carried out to ensure data reproducibility. Raw mass spectrometry data were processed as described elsewhere (Han et al. 2008. Metabolomics. 4:128-140). To identify differences in metabolite composition between untreated and treated samples, we first filtered our list of masses for metabolites that were present on one set of samples (untreated or treated) but not the other. Additionally, we averaged the mass intensities of metabolites in each group and calculated the ratios between averaged intensities of metabolites from untreated and treated samples. To assign possible metabolite identities to the masses present in only one of the sample groups or showing at least a 2-fold change in intensities between the sample groups, the monoisotopic neutral masses of interest were queried against MassTrix (http://masstrix.org), a free-access software designed to incorporate masses into metabolic pathways. Masses were searched against the Mus musculus database within a mass error of 3 ppm. Data were analyzed by unpaired t tests with 95% confidence intervals.
2011-02-08 | E-GEOD-25687 | biostudies-arrayexpress
Project description:During the colonization of hosts, bacterial pathogens are presented with many challenges that must be overcome for colonization to successfully occur. This requires bacterial sensing of the surroundings and adaptation to the conditions encountered. One of the major impediments to pathogen colonization of the mammalian gastrointestinal tract is the antibacterial action of bile. Salmonella enterica serovar Typhimurium has specific mechanisms involved in resistance to bile. Besides being resistant to it, Salmonella can also successfully multiply in bile, using it as a source of nutrients. This accomplishment is highly relevant to pathogenesis, as Salmonella colonizes the gallbladder of hosts, where it can be carried asymptomatically and promote further host spread and transmission. In order to gain insights into the mechanisms used by Salmonella to grow in bile, we studied the changes elicited by Salmonella in the chemical composition of bile during growth in vitro and in vivo through a metabolomics approach. Our data suggest that phospholipids are an important source of carbon and energy for Salmonella during growth in the laboratory as well as during gallbladder infections of mice. Further studies in this area will generate a better understanding of how Salmonella exploits this generally hostile environment for its own benefit. For in vitro studies, bile was extracted from C57BL/6 mice and used immediately. An overnight culture of Salmonella enterica serovar Typhimurium SL1344 was used to inoculate 10 ?L of bile at an approximate density of 5x10^6 cells/mL. The experiment was performed in duplicate, and a total of 2 uninfected and 2 infected bile samples were studied. Samples were incubated for 24 hours at 37 oC with shaking. After incubation, samples were centrifuged to remove bacteria and the supernatant was saved for metabolomic analyses. For in vivo studies, C57BL/6 mice were infected with approximately 10^8 bacterial cells by oral gavage. Four groups of three to four mice each were either infected with Salmonella or kept uninfected (total of 11 mice per treatment group). Five days after infection, all mice were sacrificed and bile was collected. Samples were centrifuged and supernatants saved for metabolomic analyses. Samples were prepared by mixing equal volumes of bile from three to four mice, generating three samples per treatment (uninfected and infected), which were used in the subsequent steps. Seven microliters of each sample was evaporated and the residue resuspended in 50% acetonitrine. Extracts were infused into a 12-T Apex-Qe hybrid quadrupole-FT-ICR mass spectrometer equipped with an Apollo II electrospray ionization source, a quadrupole mass filter and a hexapole collision cell. Raw mass spectrometry data were processed as described elsewhere (Han et al. 2008. Metabolomics. 4:128-140). To identify differences in metabolite composition between different groups of samples, we filtered the list of masses for metabolites which were present on one set of samples but not the other. Additionally, we calculated the ratios between averaged intensities of metabolites from each group of mice. To assign possible metabolite identities to the masses selected as described above, the monoisotopic neutral masses of interest were queried against the Human Metabolome Database (HMDB, http://www.hmdb.ca), with a tolerance of 0.001 Da.
2011-07-06 | E-GEOD-30404 | biostudies-arrayexpress