Pseudomonas savastanoi pv phaseolicola R5 treated with resveratrol (proteomics)
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Orbitrap Fusion Lumos
ORGANISM(S): Pseudomonas Savastanoi Pv. Phaseolicola R5
SUBMITTER: 
Bret Cooper
PROVIDER: MSV000090171 | MassIVE | Mon Aug 22 06:09:00 BST 2022
REPOSITORIES: MassIVE
Similar Datasets
Project description:Cells were treated with DMSO (biological triplicate) or degrader at indicated dose and time (Meta Treatment Table) and cells were harvested by centrifugation. Lysis buffer (8 M Urea, 50 mM NaCl, 50 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (EPPS) pH 8.5, Protease and Phosphatase inhibitors from Roche) was added to the cell pellets and homogenized by 20 passes through a 21 gauge (1.25 in. long) needle to achieve a cell lysate with a protein concentration between 1 - 4 mg/mL. A micro-BCA assay (Pierce) was used to determine the final protein concentration in the cell lysate. 200 µg of protein for each sample were reduced and alkylated as previously described1. Proteins were precipitated using methanol/chloroform. In brief, four volumes of methanol were added to the cell lysate, followed by one volume of chloroform, and finally three volumes of water. The mixture was vortexed and centrifuged to separate the chloroform phase from the aqueous phase. The precipitated protein was washed with three volumes of methanol, centrifuged and the resulting washed precipitated protein was allowed to air dry. Precipitated protein was resuspended in 4 M Urea, 50 mM HEPES pH 7.4, followed by dilution to 1 M urea with the addition of 200 mM EPPS, pH 8. Proteins were first digested with LysC (1:50; enzyme:protein) for 12 hours at room temperature. The LysC digestion was diluted to 0.5 M Urea with 200 mM EPPS pH 8 followed by digestion with trypsin (1:50; enzyme:protein) for 6 hours at 37 °C. Tandem mass tag (TMT) reagents (Thermo Fisher Scientific) were dissolved in anhydrous acetonitrile (ACN) according to manufacturer’s instructions. Anhydrous ACN was added to each peptide sample to a final concentration of 30% v/v, and labeling was induced with the addition of TMT reagent to each sample at a ratio of 1:4 peptide:TMT label. The 11 or 16-plex labeling reactions were performed for 1.5 hours at room temperature and the reaction quenched by the addition of hydroxylamine to a final concentration of 0.3% for 15 minutes at room temperature. Each of the sample channels were combined in a 1:1 ratio, desalted using C18 solid phase extraction cartridges (Waters) and analyzed by LC-MS for channel ratio comparison. Samples were then combined using the adjusted volumes determined in the channel ratio analysis and dried down in a speed vacuum. The combined sample was then resuspended in 1% formic acid and acidified (pH 2 - 3) before being subjected to desalting with C18 SPE (Sep-Pak, Waters). Samples were then offline fractionated into 96 fractions by high pH reverse-phase HPLC (Agilent LC1260) through an aeris peptide xb-c18 column (phenomenex) with mobile phase A containing 5% acetonitrile and 10 mM NH4HCO3 in LC-MS grade H2O, and mobile phase B containing 90% acetonitrile and 10 mM NH4HCO3 in LC-MS grade H2O (both pH 8.0). The 96 resulting fractions were then pooled in a non-continuous manner into 24 fractions and these fractions were used for subsequent mass spectrometry analysis. Data were collected using an Orbitrap Fusion Lumos mass spectrometer (Thermo Fisher Scientific, San Jose, CA, USA) coupled with a Proxeon EASY-nLC 1200 LC pump (Thermo Fisher Scientific) or an Orbitrap Eclipse Tribrid mass spectrometer (Thermo Fisher Scientific, San Jose, CA, USA) coupled with an UltiMate 3000 RSLCnano System. Peptides were separated on an EasySpray ES803a/ES803a.rev2 75 μm inner diameter microcapillary column (Thermo Fisher Scientific) or a 100 µm inner diameter microcapillary column packed with ~ 50 cm of Accucore C18 resin (2.6 µM, 100 Å, Thermo Fisher Scientific). Peptides were separated using a 190 min gradient of 6 - 27% acetonitrile in 1.0% formic acid with a flow rate of 300 or 350 nL/min. Each analysis used an MS3-based TMT method as described previously. The data were acquired using a mass range of m/z 340 – 1350, resolution 120,000, AGC target 5 x 105, maximum injection time 100 ms, dynamic exclusion of 120 seconds for the peptide measurements in the Orbitrap. Data dependent MS2 spectra were acquired in the ion trap with a normalized collision energy (NCE) set at 35%, AGC target set to 1.8 x 104 and a maximum injection time of 120 ms. MS3 scans were acquired in the Orbitrap with a HCD collision energy set to 55%, AGC target set to 2 x 105, maximum injection time of 150 ms, resolution at 50,000 and with a maximum synchronous precursor selection (SPS) precursors set to 10.
2021-07-30 | PXD023636 | Pride
Project description:Tags 126, 127N, and 128C were assigned to control replicates, 127C, 128N, and 130C were assigned to 0.5 mM SA-treated replicates, and 129C, 130N, and 131 were assigned to 1.0 mM SA-treated replicates. Labeled samples were mixed together and fractionated by high-pH reverse phase HPLC. Twelve concatenated fractions were analyzed. Peptides from each fraction were separated using a gradient of 3 to 27% of 90% acetonitrile\0.1% formic acid over 180 minutes and were electrosprayed at 2.6 kV into an Orbitrap Fusion mass spectrometer operating in data-dependent mode with positive polarity. Quadrupole isolation was enabled, and survey scans were recorded in the Orbitrap at 120,000 resolution over a mass range of 400-1500 m/z. The automatic gain control (AGC) target was set to 1,600,000 and the maximum injection time was set to 50 milliseconds (msec). The most abundant precursor ions (intensity threshold 5,000) were fragmented by collision-induced dissociation (35% energy) and fragment ions were detected in the linear ion trap (AGC 32,500, 50 msec maximum injection). Analyzed precursors were dynamically excluded for 150 seconds. Multiple MS2 fragment ions were captured using isolation waveforms with multiple frequency notches and fragmented by high energy collision-induced dissociation (65% normalized collision energy). MS3 spectra were acquired in the Orbitrap (AGC 250,000; maximum injection time 200 msec, 50,000 resolution scanning from 100-1000 m/z).
2021-07-19 | MSV000087853 | MassIVE
Project description:Cortical rat neuronal culture, lysis and proteolytic digestion Primary rat cortical neurons were generated from E18 Sprague-Dawley rat embryos with minor modifications (Swanger, Mattheyses et al. 2015, Henderson, Greathouse et al. 2019). Neurons were cultured at a density of 4x105 cells per well in 12-well culture plates (Fisher Scientific, catalog no. 353043). Neurons were cultured in Neurobasal medium (Fisher Scientific, catalog no. 21103-049) supplemented with B27 (Fisher Scientific, catalog no.17504-044). Culture maintenance included a half media change every 2-3 days. At DIV 14, neurons were either treated with 150 ng/mL recombinant NRN1 protein (Abcam, ab69755) or vehicle treated with diH2O for 6 hours. NRN1 concentration was chosen based on published data that identified a plateau in exogenous NRN1 induced effects on transient potassium currents at 150 ng/mL (Yao et al., 2012). After 6 hours neurons were washed 2x with 1 mL 1X phosphate-buffered saline (PBS). To harvest cells, 1 mL 1X PBS + protease inhibitor (Fisher Scientific, catalog no. 78426) was added and cells were centrifuged for 2300rpm for 5 minutes at 4°C. Cell pellets were lysed in 200uL 8M urea buffer and HALT protease and phosphatase inhibitor cocktail (1x final concentration). Lysates were sonicated with a probe sonicator 3 times for 10 s with 10 s intervals at 30% amplitude and cleared of cellular debris by centrifugation in a tabletop centrifuge at 18,000 rcf for 3 minutes at 4° C. Protein concentration was determined by BCA assay and one-dimensional SDS-PAGE gels were run followed by Coomassie blue staining as quality control for protein integrity and equal loading before proceeding to protein digestion. Protein homogenates (50 µg) were diluted with 50 mM NH4HCO3 to a final concentration of less than 2 M urea and then treated with 1 mM dithiothreitol (DTT) at 25°C for 30 minutes, followed by 5 mM iodoacetimide (IAA) at 25°C for 30 minutes in the dark. Protein was digested with 1:100 (w/w) lysyl endopeptidase (Wako) at 25°C for 2 hours and further digested overnight with 1:50 (w/w) trypsin (Pierce) at 25°C. Resulting peptides were desalted with a Sep-Pak C18 column (Waters) and dried under vacuum.
2023-07-20 | PXD040867 | Pride
Project description:To achieve deep coverage of M. smegmatis proteome, 240 μg proteins were reduced with 5 mM of dithiothreitol (DTT), alkylated with 20 mM of iodoacetamide (IAA). The alkylated proteins were separated by a 10% SDS-PAGE for 8 cm, and stained with Coomassie Blue G250. Gel lane was excised into 13 fractions based on the molecular wight (MW) and protein abundance, and digested with and Ac-LysargiNase (Zhang et al., 2019) (12.5 ng/μL) at 37 °C for 12-24 h. The extracted peptides were desalted with a homemade C18 StageTip (Zhai et al., 2013), dried and dissolved in loading buffer (1% acetonitrile, ACN and 1% formic acid, FA) for MS analysis. The dissolved peptides (500 ng) were analyzed as described previously. Briefly, the liquid chromatography tandem mass spectrometry (LC-MS/MS) consisted of an EASY-nLC 1200 system (Thermo Fisher Scientific, San Jose, CA, United States) equipped with a self-packed capillary column (75 μm i.d. × 15 cm, 3 μm C18 reversed-phase fused silica) coupled to an Orbitrap Fusion Lumos (Thermo Fisher Scientific). For full MS scans, the automatic gain control (AGC) was 5.0 × 105, the scan ranged from 300 to 1,400 m/z at a resolution of 1.2 × 105 and a maximum injection time (MIT) of 50 ms. For the MS2 scan, only spectra with a charge state of 2-6 were selected for fragmentation by higher energy collision-induced dissociation (HCD) with a normalized collision energy of 32%, AGC of 1 × 105, and MIT of 35 ms. The dynamic exclusion was set to 30 s.
2022-09-29 | PXD037080 |
Project description:To achieve deep coverage of M. smegmatis proteome, 240 μg proteins were reduced with 5 mM of dithiothreitol (DTT), alkylated with 20 mM of iodoacetamide (IAA). The alkylated proteins were separated by a 10% SDS-PAGE for 8 cm, and stained with Coomassie Blue G250. Gel lane was excised into 13 fractions based on the molecular wight (MW) and protein abundance, and digested with Ac-Trypsin (Wu et al., 2016) (12.5 ng/μL) at 37 °C for 12-24 h. The extracted peptides were desalted with a homemade C18 StageTip (Zhai et al., 2013), dried and dissolved in loading buffer (1% acetonitrile, ACN and 1% formic acid, FA) for MS analysis.The dissolved peptides (500 ng) were analyzed as described previously. Briefly, the liquid chromatography tandem mass spectrometry (LC-MS/MS) consisted of an EASY-nLC 1200 system (Thermo Fisher Scientific, San Jose, CA, United States) equipped with a self-packed capillary column (75 μm i.d. × 15 cm, 3 μm C18 reversed-phase fused silica) coupled to an Orbitrap Fusion Lumos (Thermo Fisher Scientific). For full MS scans, the automatic gain control (AGC) was 5.0 × 105, the scan ranged from 300 to 1,400 m/z at a resolution of 1.2 × 105 and a maximum injection time (MIT) of 50 ms. For the MS2 scan, only spectra with a charge state of 2-6 were selected for fragmentation by higher energy collision-induced dissociation (HCD) with a normalized collision energy of 32%, AGC of 1 × 105, and MIT of 35 ms. The dynamic exclusion was set to 30 s.
2022-09-29 | PXD037081 |
Project description:2-cell (E1.5) stage embryos were cultured in normal KSOM+AA conditions until E3.5 +2h and thereafter 100 embryos each were moved to control or p38-MAPKi conditions and cultured for another 7 hours (E3.5 +9h). The embryos were then washed through pre-warmed (37˚C) Hank’s balanced salt solution (HBSS, Sigma-Aldrich; Cat. No. H9269) and lysed by moving to a 1.5ml centrifuge tube containing about 15µl of SDT-lysis buffer (4% (w/v) SDS, 100 mM Tris-HCl pH 7.6, 0.1 M DTT). Cell lysis was performed by incubating the tubes in a 95˚C thermoblock for 12 minutes, brief centrifugation at 750 rpm, cooling to room temperature and storage at -80˚C. Individual protein solutions were processed by filter-aided sample preparation (FASP) method with some modifications (see the associated publication for more details). Resulting peptides were cleaned by liquid-liquid extraction (3 iterations) using water saturated ethyl acetate. 1/10th of the FASP eluate was taken out for direct LC-MS measurements, evaporated completely in SpeedVac concentrator (Thermo Fisher Scientific). Peptides were further transferred into LC-MS vials using 50μL of 2.5% formic acid (FA) in 50% acetonitrile (ACN) and 100μL of pure ACN and with addition of polyethylene glycol (final concentration 0.001%) and concentrated in a SpeedVac concentrator. Phosphopeptides were enriched from the remaining 9/10th of the cleaned FASP eluate after complete solvent evaporation (SpeedVac concentrator) using High-Select™ TiO2 Phosphopeptide Enrichment Kit (Thermo Fisher Scientific) according to manufacturer protocol. Phosphopeptide standards (0.1 pmol of MS PhosphoMix 1, 2, 3 Light; Sigma-Aldrich, St. Louis, Missouri, USA) was added to suspended sample in binding/equilibration buffer. Flow-through fraction was dried and used for second enrichment step using High-Select™ Fe-NTA Phosphopeptide Enrichment Kit (Thermo Fisher Scientific, Waltham, Massachusetts, USA) according to manufacturer protocol. Resulting phosphopeptides were extracted into LC-MS vials by 2.5% FA in 50% ACN and 100% ACN with addition of polyethylene glycol (final concentration 0.001%) and concentrated in a SpeedVac concentrator). LC-MS/MS analyses of all peptide mixtures (2 peptide solutions for each sample – 1) not enriched; 2) enriched on phosphopeptides using TiO2 enrichment kit) were done using RSLCnano system connected to Orbitrap Fusion Lumos mass spectrometer (Thermo Fisher Scientific). Prior to LC separation, tryptic digests were online concentrated and desalted using trapping column (100 μm × 30 mm, column compartment temperature of 40˚C) filled with 3.5-μm X-Bridge BEH 130 C18 sorbent (Waters). After washing of trapping column with 0.1% FA, the peptides were eluted (flow rate - 300nl/min) from the trapping column onto an analytical column (Acclaim Pepmap100 C18, 3 µm particles, 75 μm × 500 mm; column compartment temperature of 40˚C, Thermo Fisher Scientific) by using 50 or 100 minutes long nonlinear gradient program (1-56% of mobile phase B; mobile phase A: 0.1% FA in water; mobile phase B: 0.1% FA in 80% ACN) for analysis of phosphopeptide enriched fractions or not enriched peptide mixtures, respectively. Equilibration of the trapping column and the analytical column was done prior to sample injection to sample loop. The analytical column outlet was directly connected to the Digital PicoView 550 (New Objective) ion source with sheath gas option and SilicaTip emitter (New Objective; FS360-20-15-N-20-C12) utilization. ABIRD (ESI Source Solutions) was installed. MS data were acquired in a data-dependent strategy with cycle time for 3 seconds and with survey scan (350-2000 m/z). The resolution of the survey scan was 60000 (200 m/z) with a target value of 4×105 ions and maximum injection time of 50ms. HCD MS/MS (30% relative fragmentation energy, normal mass range) spectra were acquired with a target value of 5.0x104. The MS/MS spectra were recorded in Orbitrap at resolving power of 30,000 or 15,000 (200 m/z) and the maximum injection time for MS/MS was 500 or 22 ms for analysis of phosphopeptides enriched fraction or non-enriched peptide mixture, respectively. Dynamic exclusion was enabled for 60 seconds after one MS/MS spectra acquisition. The isolation window for MS/MS fragmentation was set to 1.6 m/z.
2021-07-12 | PXD025754 | Pride
Project description:R5 was cultured in 10 mL Luria broth with 1.0 mM resveratrol or without (but with 50 uL DMSO) at 28 C at 200 rpm on a shaking platform until the cultures reached an average O.D. of 1.0 at 600 nm. Five replicate cultures were used for metabolomics experimentation. The samples were centrifuged at 5,000 x g for 10 min., washed once in 1 mL phosphate buffered saline, centrifuged at 5,000 x g for 10 min., resuspended in 1 mL of 1:1:1:1 acetone/acetonitrile/methanol/water and 1,2500 pmol prednisone, and pulverized in the bead mill. Two matrix blank samples were prepared the same way starting with 10 mL Luria broth (without R5 and without resveratrol). The milled extracts were centrifuged for 20 minutes at 12,000 x g. The supernatants were transferred to fresh tubes and centrifuged again. The supernatants were transferred to glass vials and dried under vacuum. The residues were resuspended in 115 ul 50% methanol/0.1% formic acid. Fifteen ul of each sample was pooled to create a QC sample. Five ul of the samples were separated on a 150 x 2.1 mm Hypersil GOLD VANQUISH HPLC column with 1.9 um particles (Thermo Fisher Scientific) coupled to a Vanquish HPLC pump (Thermo Fisher Scientific) controlling a 10-minute linear gradient from 0% to 95% acetonitrile and 0.1% formic acid at a flow rate of 0.2 mL per minute. Eluent was electrosprayed at 3.5 kV positive polarity into an Exploris 240 mass spectrometer (Thermo Fisher Scientific) using an internal mass calibrant. Sheath gas was 35, auxiliary gas was 7, and sweep gas was 1 (arbitrary units). The ion transfer tube temperature was 325 C and the vaporizer temperature was 275 C. Advanced peak determination, mild trapping, and internal mass calibration was enabled. Default charge state was 1 and the expected peak width was 6 sec. AcquireX software was used to create a background ion exclusion list from the matrix blank sample and an inclusion ion list from the QC sample. Four subsequent injections of the QC were performed to generate MS2 spectra. After each QC injection, the resolved ions were appended to the exclusion list. Survey scans were recorded in the Orbitrap at 60,000 resolution over a mass range of 70-800 m/z. The RF lens was 70%. Monoisotopic precursor selection was enabled, the minimum intensity was 5,000, and charge states were filtered to 1. Precursors selected within a 1.0 Da isolation window were fragmented by high energy collision-induced dissociation (30%, 50%, 70% normalized stepped collision energy), and fragment ions were resolved in the Orbitrap at 30,000 resolution. Subsequently, all test samples were analyzed alongside QC and matrix blank samples in the following order: Matrix blank1, QC1, sample replicates 1, Blank2, QC2, sample replicates 2, etc. Survey scans were recorded in the Orbitrap at 120,000 resolution over a mass range of 70-800 m/z. The RF lens was 70%.
2022-08-22 | MSV000090172 | MassIVE
Project description:Orbitrap Fusion (Thermo Fisher Scientific) LC-MS/MS analyses were performed on an Easy-nLC 1000 liquid chromatography system (Thermo Fisher Scientific) coupled to an Orbitrap Fusion via a nano-electrospray ion source. Tryptic peptides were dissolved with a loading buffer (acetonitrile and 0.1% formic acid), and were eluted with a flow rate of 350 nL/min. Survey scans were acquired after an accumulation of 5×105 ions in the Orbitrap for m/z 300-1,400 using a resolution of 120,000 at m/z. The top speed data-dependent mode was selected for fragmentation in the cell at a normalized collision energy of 32%, and fragment ions were then transferred into the ion trap analyzer with the AGC target at 5×103 and maximum injection time at 35 ms. The dynamic exclusion of previously acquired precursor ions was enabled at 18 s. The Proteome Discoverer 1.4.1.14 was used for analysis of the protein spectrum. Oxidation (Methionine) and acetylation (Protein-N term) were chosen as variable modifications, cysteine carbamidomethylation was chosen as a fixed modification. Two missed cleavage sites for trypsin were allowed. The intensity-based absolute quantification (iBAQ)-based protein quantification were performed by an in-house software. The interaction of SNT-related differentially expressed proteins was investigated by STRING 11.0 (https://string-db.org). The differentially expressed protein interaction network (high reliability, interaction score > 0.4, PPI enrichment P-value < 1.0×10 -16) was selected for the analysis.
2021-09-09 | PXD018509 | Pride
Project description:Human primary macrophages were infected with influenza A virus (H3N2/Udorn strain, HA 256) for 6 hrs or left untreated. Cells were collected and lysed with HEPES lysis buffer (50 mM HEPES, 150 mM NaCl, 1 mM EDTA, 1 % NP-40, pH 7.4) including protease and phosphatase inhibitor cocktails. The cell lysates were centrifuged and the supernatant was collected and the protein content was measured with Bio-Rad DC™ protein assay (Bio-Rad). The proteins were reduced, alkylated, and enzymatically digested in-solution with trypsin. The digestion was stopped by adding FA (final c = 1 %). The samples were centrifuged 9168 x g for 10 min and desalted with Sep-Pak Vac RP C18 cartridges (Waters, MA, USA), following fractionation by strong cation exchange chromatography (SCX). The peptides were separated on a 200 x 4.6 mm, 5 μm, 200 Å PolySULFOETHYL A™ column (PolyLC, USA). The fractions were vacuum centrifuged and desalted as before, following phosphopeptide-enrichment with PHOS-Select™ Iron Affinity Gel (Sigma Aldrich, MO, USA). LC-MS/MS was performed with a Q Exactive hybrid quadrupole-orbitrap tandem mass spectrometer coupled to an EASY-nLC 1000 nanoflow liquid chromatograph (Thermo Fisher Scientific). A 100 μm x 3 cm trap column and a 75 μm x 15 cm analytical column were in-house packed with Magic C18AQ resin (200 Å, 5 μm; Michrom Bioresources). The mobile phases were 2% acetonitrile, 0.2% formic acid (A) and 95% acetonitrile, 0.2% formic acid (B). LC gradient elution condition was 2% B (0 min), 20% B (70 min), 40% B (100 min), and then 100% B (105-110 min), with a flow rate of 300 nl/min. Data dependent acquisition was performed in positive ion mode. MS spectra were acquired from m/z 300 to m/z 2000 at a resolution of 70,000 at m/z 200 with a target value of 1,000,000 and maximum injection time of 120 ms. The 10 most abundant precursor ions of which charge states were 2+ or higher were selected for higher energy collisional dissociation (HCD) with an isolation window of 2 and normalized collision energy of 30. MS/MS spectra were acquired at a resolution of 17,500 at m/z 200 with a target value of 50,000, maximum injection time of 250 ms, and the lowest mass fixed at m/z 100. Dynamic exclusion duration was 30 s.
2016-08-08 | PXD001620 | Pride
Project description:Female Sprague-Dawley rats were randomly separated into two groups: i) trained (Ex group) and ii) sedentary (Cont group). Animals from the Ex group were adapted to treadmill exercise for two consecutive weeks, involving a gradual increase in the running time till 60 min/day at 20 m/min, 0% grade, 5 days/week. This exercise program remained constant until the end of the 54 weeks. Mitochondria isolation from 10 animals (5 Ex group and 5 Cont group) was performed using the conventional methods of differential centrifugation. Mitochondrial protein extracts were reduced with dithiothreitol, alkylated with iodoacetamide and digested with trypsin using the FASP procedure (18). Briefly, each sample was solubilized in 4 % SDS, 0.1 M DTT, 0.1 M HEPES and incubated for 30 min at 60 C. Then, samples were mixed with 0.2 mL of a solution of 8 M Urea, 0.1 M HEPES, pH 8.5 (UH solution), loaded into the filtration devices (3k Microcon, Millipore), centrifuged at 14,000 g for 20 min, and washed twice with UH solution. After centrifugation, the concentrates were alkylated with 50 mM iodoacetamide in UH solution (dark, 25 C, 20 min), and washed twice with UH solution. The concentrate was diluted with 0.1 mL of 50 mM ammonium bicarbonate (ABC) and digested overnight (37 C) with the addition of 2 ug of trypsin diluted in 30 uL of 50 mM ABC. The resulting tryptic peptides were collected by centrifugation and the filter were washed twice with 50 uL of 50 mM ABC. Eluted peptides were acidified with 10 uL of formic acid and cleaned up on a homemade Empore C18 column (3M, St. Paul, MN, USA) (ref) for subsequent phospho-enrichment and/or analysis by LC-MS/MS. The dried protein digest was dissolved with 10 uL (3 % ACN, 0.1 % TFA), diluted 1:5 with loading buffer (1 M glycolic acid, 5 % TFA, 80 % ACN) and phosphopeptides were enriched on TiO2-beads as previously described (19). Briefly 5 mg of "Titansphere TiO2 5 um" were suspended in 100 uL of 100 % ACN, immobilized in a pipette-column and washed using 5 uL of loading buffer. Each sample was loaded in each pipette-column and then washed with 30 uL of washing buffer (1 % TFA, 80 % ACN). Phosphopeptides were eluted from the beads with 25 uL of 25 % ACN (v/v) containing 25 % NH4OH (m/v), acidified with 10 uL of 10 % TFA and vacuum- concentrated to approximately 4 uL. Samples were finally diluted to 10 uL with H2O + 0.1% formic acid prior to injection. The peptides mixtures were analyzed by online nanoflow liquid chromatography tandem mass spectrometry (nanoLC-MS/MS) on an EASY-nLC system (Proxeon Biosystems, Odense, Denmark) connected to the LTQ Orbitrap Velos instrument (Thermo Fisher Scientific, Bremen, Germany) through a nanoelectrospray ion source. Six microliters of the peptide mixture were auto-sampled directly onto the analytical HPLC column (120 mm x75 um I.D., 3 um particle size (Nikkyo Technos Co., Ltd.) with a 120-min gradient from 5 % to 50 % ACN in 0.1 % FA. The effluent from the HPLC column was directly electrosprayed into the mass spectrometer. The LTQ Orbitrap Velos instrument was operated in data-dependent acquisition mode to automatically switch between full scan MS and MS/MS acquisition. The MS survey scan was performed in the FT cell recording a window between 350 and 2000 m/z. The resolution was set to 60 000, and the automatic gain control was set to 1,000,000 ions with a maximal acquisition time of 400 ms. The 20 most intense peptide ions with charge states great than or equal to 2 were sequentially isolated to a target value of 5,000 and fragmented in the high-pressure linear ion trap by low-energy CID with normalized collision energy of 35% Q value of 0.25, and an activation time of 10 ms. Raw files were processed using Proteome Discoverer version 1.3 (Thermo Fisher Scientific, Bremen). Peak lists were searched using Mascot software version 2.3 (Matrix Science, UK) against a SwissProt database containing entries corresponding to Rattus norvegicus (version of July 2012), a list of common contaminants, and all the corresponding decoy entries. Trypsin was chosen as enzyme and a maximum of two miscleavages were allowed. Carbamidomethylation (C) was set as a fixed modification, whereas oxidation (M) and phosphorylation (STY) were used as variable modifications. Searches were performed using a peptide tolerance of 7 ppm, a product ion tolerance of 0.5 Da. Resulting data files were filtered for FDR less than 1 % at peptide level.
2014-02-14 | PXD000354 | Pride