Proteomic analysis of bone marrow supernatants.
Ontology highlight
ABSTRACT:
INSTRUMENT(S): QExactive
ORGANISM(S): Mus Musculus (ncbitaxon:10090)
SUBMITTER: 
Panayotis Verginis
PROVIDER: MSV000095541 | MassIVE | Wed Aug 07 08:34:00 BST 2024
SECONDARY ACCESSION(S): PXD054676
REPOSITORIES: MassIVE
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Project description:The chromatin fraction was isolated from 5x107 HeLa cells. Chromatin was digested in 100 mL of MNase (40 units/ mL ) reaction buffer for 3 min at 37 °C in a thermomixer (1,400 rpm). After addition of 10 L EGTA (25mM) to inactivate MNase, soluble digested chromatin was collected by 13,000 rpm centrifuge for 5 min. 10 mg of Pol II antibody was conjugated to magnetic protein A beads. The supernatant was diluted with 400 mL of NET-2 buffer and pSer2-Pol II antibody-conjugated beads were added. Incubated the IP reaction at 4 °C for 1 hr. The beads were washed with 1 mL of NET-2 buffer six times and 100 mL of 1xPNKT (1xPNK buffer and 0.05% Triton X-100) buffer once. Washed beads were incubated in 50 mL PNK reaction mix (1xPNKT, 1 mM ATP and 0.05 U/ml T4 PNK (NEB)) in Thermomixer at 37 °C, 1,400 rpm for 6 min. Beads were washed with 1 mL of NET-2 buffer once and RNA was extracted with Trizol reagent. RNA was suspended in urea Dye (7M Urea, 1xTBE, 0.1% BPB and 0.1% XC) and resolved on 6% TBU gel (Invitrogen) at 200 V for 5 min. Gels with 30-160 nt RNAs were collected. 0.2 mL tube was prepared with holes made with 25G needle and placed in a 1.5 mL tube. Gel fragments were placed in the layered tube and broken down by centrifugation at 12,000 rpm for 1 min. The small RNAs were eluted from gel using RNA elution buffer (1 M NaOAc and 1 mM EDTA) at 25 °C for 1 hr in Thermomixer (900 rpm). Eluted RNA was purified with SpinX column (Coster) with 2 glass filters (Millipore) and the flow-through RNA was ethanol precipitated.
2019-10-15 | GSE134102 | GEO
Project description:Washed three times in NaCl (150 mM). Cells were resuspended in 1 ml TSU buffer (50 mM Tris pH 8.0, 0.1% SDS, 2.5 M urea) and lysed by two freeze-thaw cycles in liquid nitrogen. Lysate proteins (40 ug) were separated and digested. Digested peptides were separated by nano-LC using an Ultimate 3000 HPLC and autosampler system (Dionex; Amsterdam, Netherlands). Samples (1 ul) were concentrated and desalted onto a micro C18 pre-column (500 um×2 mm, Michrom Bioresources; Auburn, CA, USA) with H2O:CH3CN (98:2, 0.05% trifluoroacetic acid) at 15 ul min−1. After a 4 min wash the pre-column was switched (Valco 10 port valve; Dionex) into line with a fritless nano column (75 u×~10 cm) containing C18 media (5 u, 200 A Magic; Michrom) manufactured according to Gatlin. Peptides were eluted using a linear gradient of H2O:CH3CN (98:2, 0.1% formic acid) to H2O:CH3CN (64:36, 0.1% formic acid) at 250 nl min−1 over 30 min. High voltage (2000 V) was applied to low volume tee (Upchurch Scientific) and the column tip positioned ~0.5 cm from the heated capillary (T = 280 degrees C) of an Orbitrap Velos (Thermo Electron; Bremen, Germany) mass spectrometer. Positive ions were generated by electrospray and the Orbitrap operated in data dependent acquisition mode (DDA). A survey scan m/z 350–1750 was acquired in the Orbitrap (Resolution = 30,000 at m/z 400, with an accumulation target value of 1,000,000 ions) with lockmass enabled. Up to the 10 most abundant ions (>5,000 counts) with charge states >+2 were sequentially isolated and fragmented within the linear ion trap using collisionally induced dissociation with an activation q = 0.25 and activation time of 30 ms at a target value of 30,000 ions. M/z ratios selected for MS/MS were dynamically excluded for 30 s. Peak lists were generated using Mascot Daemon/extract_msn (Matrix Science, Thermo; London, England) using the default parameters, and submitted to the database search program Mascot (version 2.1, Matrix Science). Search parameters were: Precursor tolerance 4 ppm and product ion tolerances +/-0.4 Da Oxidation (M) and Carbamidomethyl (C) specified as variable modifications Enzyme specificity was trypsin, 1 missed cleavage was possible
2014-04-28 | PXD000505 | Pride
Project description:Bacteria were washed three times in NaCl (150 mM). Cells were resuspended in 1 ml TSU buffer (50 mM Tris pH 8.0, 0.1% SDS, 2.5 M urea) and lysed by two freeze-thaw cycles in liquid nitrogen. Lysate proteins (40 ug) were separated and digested. Digested peptides were separated by nano-LC using an Ultimate 3000 HPLC and autosampler system (Dionex; Amsterdam, Netherlands). Samples (1 ul) were concentrated and desalted onto a micro C18 pre-column (500 um×2 mm, Michrom Bioresources; Auburn, CA, USA) with H2O:CH3CN (98:2, 0.05% trifluoroacetic acid) at 15 ul min−1. After a 4 min wash the pre-column was switched (Valco 10 port valve; Dionex) into line with a fritless nano column (75 u×~10 cm) containing C18 media (5 u, 200 A Magic; Michrom) manufactured according to Gatlin. Peptides were eluted using a linear gradient of H2O:CH3CN (98:2, 0.1% formic acid) to H2O:CH3CN (64:36, 0.1% formic acid) at 250 nl min−1 over 30 min. High voltage (2000 V) was applied to low volume tee (Upchurch Scientific) and the column tip positioned ~0.5 cm from the heated capillary (T = 280 degrees C) of an Orbitrap Velos (Thermo Electron; Bremen, Germany) mass spectrometer. Positive ions were generated by electrospray and the Orbitrap operated in data dependent acquisition mode (DDA). A survey scan m/z 350–1750 was acquired in the Orbitrap (Resolution = 30,000 at m/z 400, with an accumulation target value of 1,000,000 ions) with lockmass enabled. Up to the 10 most abundant ions (>5,000 counts) with charge states >+2 were sequentially isolated and fragmented within the linear ion trap using collisionally induced dissociation with an activation q = 0.25 and activation time of 30 ms at a target value of 30,000 ions. M/z ratios selected for MS/MS were dynamically excluded for 30 s. Peak lists were generated using Mascot Daemon/extract_msn (Matrix Science, Thermo; London, England) using the default parameters, and submitted to the database search program Mascot (version 2.1, Matrix Science). Search parameters were: Precursor tolerance 4 ppm and product ion tolerances +/-0.4 Da; Oxidation (M) and Carbamidomethyl (C) specified as variable modifications, Enzyme specificity was trypsin, 1 missed cleavage was possible
2014-04-28 | PXD000504 | Pride
Project description:This series represents a group of five samples (from sigmoid colon biopsies of clinically normal Patients A-E) profiled by a publicly available cDNA-based platform (GPL284) and a commercial oligonucleotide-based platform (GPL91). Sample RNA extraction: Biopsies taken during endoscopic analysis were immediately snap-frozen in liquid nitrogen and at no time prior to or during subsequent sample manipulation were the samples allowed to thaw. Standard laboratory procedures to eliminate the presence of RNases, including the use of RNase free plastic-ware, heat baked glassware, molecular biology grade chemicals and DEPC-treated solutions, were adopted. Frozen biopsies were crushed to a fine powder under liquid nitrogen using a manual crusher with a teflon head (Omnilab) and total RNA was isolated using the RNeasy Mini Kit (Qiagen) according to the manufacturers protocol, with minor modifications that improved RNA yields and purity in our hands. In brief, crushed biopsy samples were lysed in an appropriate volume of Buffer RLT (typically 600 µL/20 mg tissue). To facilitate complete lysis, samples were allowed to stand at room temperature for 5-10 min before vortexing. The lysate was homogenized by addition to a QIA shredder column (Qiagen) and centrifuged at 14,000 rpm for 2 min. The resulting supernatant was centrifuged at 14,000 rpm for 3 min to pellet any cell debris. One volume of 70% ethanol was added to the cleared lysate, added to the RNeasy column and centrifuged at 10,000 rpm for 15 sec. Bound RNA was washed with the addition of RW1 buffer to the column and allowed to stand at room temperature for 10 min followed by centrifugation at 10,000 rpm for 15 sec. DNase 1 incubation mix (Stock: 273 kunits; RNase-free DNase Set, Qiagen) was added directly to the spin column membrane and digestion of any contaminating genomic DNA was carried out at room temperature for 30 min. The column was washed with RWI buffer and the DNase treatment step was repeated. The bound RNA was washed with RW1 buffer and centrifuged at 10,000 rpm for 15 sec three times, followed by two additional wash and centrifugation steps with RPE buffer. Finally, purified RNA was eluted off the column with RNase-free water. RNA concentration and purity was determined spectrophotometrically at A260/A280 and was determined to be intact as assessed by formaldehyde gel electrophoresis. The presence of genomic DNA contamination was assessed by PCR amplification of GAPDH using standard PCR conditions and the following primers: GAPDH_F2-5’- ACCCACTCCTCCACCTTTGAC-3’, GAPDH_R2- 5’-CTGTTGCTGTAGCCAAATTCGT-3’. RNA was re-treated with DNase if necessary. Upon confirming the quality of the RNA (intact and free of genomic DNA), 15 µg of total RNA from each of the five biological replicates was used for expression screening on either the Affymetrix or the clone-based filter platform. Keywords: parallel sample
2003-12-14 | GSE405 | GEO
Project description:Purpose: Investigation of DDX41 chromatin binding sites in U2OS cells Method: Expression of DDX41-GFP was induced for 48 hours before crosslinking using 1µg/ml docycycline. Control cells were not induced with doxycline. Cells were mildly crosslinked using 1% FA for 2 min at RT. Concanavalin A-coated beads were activated in Binding Buffer (20 mM Hepes-KOH pH 7.9, 10 mM KCl, 1mM CaCl2, 1 mM MnCl2).1*10^6 U2OS cells were washed twice with Wash Buffer (Hepes-NaOH pH7.5, 150 mM NaCl, 0.5 mM Spermidine, 1 mM protease inhibitor) at room temperature and afterwards immobilized on the activated beads in 1 ml Wash Buffer. Cells were permeabilized with 0.05% digitonin in Wash buffer for 4 min at RT. 1 µg Nanobody-GFP-MNase (in-house protein production, PMID:25362362) binding was performed at 4°C for 30 min in 0.05% digitonin-Wash buffer. After 2x washing, the MNase was activated by adding 3mM CaCl2 on ice for 30 min. 2x Stop Buffer (68 µl 5M NaCl, 40 µl 0.5 M EDTA, 20 µl 0.2 M EGTA, 10 µl 5% digitonin, 5 µl 10mg/ml RnaseA, )) was mixed with the samples to stop the reaction. Chromatin fragments were released by incubating the samples for 20 minutes at 37°C and centrifugation at 16.000×g for 10 minutes at 4°C. Supernatants were incubated at 70°C in the presence of 0.1% SDS and 5 µg proteinase K. Before library preparation, the DNA was recovered by phenol-chloroform extraction Results: We succesfully mapped DDX41 binding sites on cromatin in U2OS cells. DDX41 preferentially binds in the promoter region of genes.
2021-11-17 | GSE183083 | GEO
Project description:We reported that the microRNA profiling of exosome isolated from 58 cerebrospinal fluid (CSF) of 38 medulloblastoma (MBL) patient with or without letomeningeal metastases (LM). CSF exosome was precipitated using Exo2DTM for RNA assay (EXOSOME plus, Suwon, South Korea) according to the manufacture’s protocol (Kim, et al. 2017). 2 ml of CSF were added to Exo2DTM reagent B following mixing by inverting, and incubated at room temperature for 30 min. The supernatant was discarded and the exosome containing pellet was resuspended in 100 ul of PBS to further RNA isolation. Total RNA was extracted from the CSF exosome fraction using a microRNA purification kit (Norgen Biotek corp., Thorold, Canada) according to the manufacture’s protocol. Briefly, samples were mixed with lysis buffer, and the lysate was added to absolute ethanol. The lysate was applied up to the column and centrifuged at 8,000 rpm for 1 min. The column was washed with wash solution and centrifuged at 14,000 rpm for 1 min. Finally, the column was applied to 20 ul of elution solution and centrifuged at 14,000 rpm for 2 min, and the flow-through was stored at –80 ℃ for storage. RNA precipitates were quantified and qualified with Bioanalyzer Pico 6000 Chip (Agilent Technologies, Santa Clara, CA). The 10 ng of total RNA was provided to the cDNA library generation using SMARTer smRNA-Seq kit (Illumina Inc., San Diego, CA), according to the user manual. The cDNA library was subjected to sequencing using Truseq SBS Kit and HiSeq 2500 System (Illumina Inc., San Diego, CA), according to user guide.
2020-09-15 | GSE157916 | GEO
Project description:Using laser capture microdissection to isolate over 100 specific cell populations, we report the profiling of prostate cancer progression from benign epithelium to metastatic disease. By analyzing these expression signatures in the context of over 15,000 â??molecular conceptsâ??, or sets of biologically connected genes, we generated an integrative model of prostate cancer progression. Keywords: disease state analysis Experiment Design: â?¢ Type of experiment: This study used microarray experiments to profile prostate cancer progression through the isolation of pure cell populations using laser capture microdissection (LCM) and OmniPlex Whole Transcriptome (WTA) Amplification. â?¢ Experimental factors: This study profiled various pure cell populations isolated by LCM from prostate tissue. â?¢ The number of hybridizations performed in the experiment: A total of 104 hybridizations were performed. â?¢ The type of reference used for the hybridizations: A single commercially available pool of benign prostate tissue (CPP, Clontech) was used as the reference in all hybridizations. For the reference sample, 10 ng of CPP total RNA was converted into a WTA cDNA library in a volume of 25 µl and five 5 µl aliquots were amplified by WTA PCR and purified. Five ng aliquots of the pooled products were subjected to a second WTA PCR amplification in the presence of amino-allyl dUTP and all products were pooled before labeling to ensure equal representation across all of the hybridizations. â?¢ Hybridization design: For all hybridizations, the experimental prostate sample isolated by LCM was labeled with Cy5 and the common reference of benign pooled prostate as described above was labeled with Cy3. â?¢ Quality control steps taken: In order to assess biological and technical reproducibility, we captured identical regions from two specimens (PCA_11 and MET_HR_3) and subjected one sample, PCA_30, to two hybridizations. For PCA_11, adjacent regions of the same section were captured and treated as separate samples. For MET_HR_3, two separate foci of the liver metastasis (from separate frozen blocks) were captured and treated as separate samples. For PCA_30, two aliquots of the primary WTA PCR products were separately subjected to a second round of WTA PCR amplification. Replicates from PCA_30 and MET_HR_3 were also hybridized to arrays from each of the print runs utilized in this study. Samples used, extract preparation and labeling: â?¢ The origin of the biological sample (for instance, name of the organism, the provider of the sample) and its characteristics: All samples used were of human origin. The table in the MIAME Checklist (Supplmentary Methods) summarizes the samples used. Hybridizations are named according to the class of sample profiled and the background color is the same as shown in Figure S3. Two print runs were used during the course of the study and the indicated run for each hybridization is given. For prostate cancer samples, the Gleason patterns present on the sample section used are indicated, as well as the Gleason patterns of the actual cells isolated by LCM. A unique case number for all profiled samples is given. Descriptions of samples are given where applicable, including the location of metastatic foci. â?¢ Manipulation of biological samples and protocols used: Laser Capture Microdissection (LCM) was performed from frozen tissue sections with the SL Microtest device using µCUT software (MMI). Approximately 10,000 cells were captured for each sample. Serial sections were used if cells could not be obtained from a single section. Total RNA was isolated from captured cells with the RNAqueous Micro kit (Ambion) and treated with DNAse I according to the manufacturer's instructions. RNA quantification was perfomed using Ribogreen (Molecular Probes). â?¢ Protocol for preparing the hybridization extract: For each sample, total RNA (~10ng) in a volume of 25 µl was converted into an OmniPlex WTA cDNA library and amplified by WTA PCR using reagents and protocols according to the beta-commercial TransPlex WTA kit (Rubicon Genomics, Ann Arbor, MI). For each sample, a single 10 µl aliquot of the WTA cDNA library was amplified by WTA PCR and products were purified. Four or five 5 ng aliquots of product were subjected to a second WTA PCR amplification in the presence of amino-allyl dUTP for post amplification labeling and products were pooled before proceeding with the hybridization. Yields after all WTA PCR amplifications were between 2 to 5 μg per reaction, and reaction progress was monitored in real time using SYBR green I (Molecular Probes) on the iCycler IQ (BioRad) or ABI 7300 Real Time PCR system (Applied Biosystems). Real-time PCR amplifications were terminated at or before plateau phase as measured by fluorescence incorporation to preserve maximum representation. â?¢ Labeling protocol(s): For all WTA amplified cDNA samples with amino-allyl dUTP incorporated (10-20 ï?g), nuclease free water was added to 500 ï?l, the sample was transferred to a Microcon YM-30 filter, and centrifuged at 13,000 rcf at RT for 12 minutes. The spin column was inverted in a new collection tube and centrifuged at 13,000 rcf for 2 min at RT. The amount of sample was measured and the volume was adjusted to 5 ï?l with nuclease free water. For labeling, 5 ï?l of 1 M sodium bicarbonate (pH 9.0) was added and allowed to incubate at RT for 15 min. Nine ï?l of anhydrous DMSO were added to Mono Reactive Cy3 and Cy5 dye packs (Amersham, Buckinghamshire, England), mixed thoroughly, and 1 ï?l of the proper dye was added to each sample. The labeling mixture was incubated in the dark at RT for 1 hour. The reaction was stopped by the addition of 9 ï?l of 4 M Hydroxylamine for 15 min. For each labeling mixture, RNase free water was added to 100 ï?l, 500 ï?l of PB buffer was added and Cy3 and Cy5 mixtures were added to separate Qiaquick (Qiagen, Valencia, CA) spin columns and centrifuged at 13,000 rcf. Columns were washed twice with 700 ï?l of buffer PE, and centrifuged dry at 13,000 rcf for 2 min. To elute, 60 ï?l of EB buffer was placed on the column, incubated for 5 min and centrifuged at 13,000 rcf for 1 min. The Cy3 labeled and Cy5 labeled cDNA for each hybridization were mixed and 1.5 ï?l were used for analysis on a ND-1000 spectrophotometer. â?¢ External controls (spikes): Not utilized Hybridization procedures and parameters: â?¢ The protocol and conditions used during hybridization, blocking and washing: For hybridization, 40 ï?g of human Cot-1 DNA (Invitrogen, Carlsbad, CA) was added to 120 ï?l of labeled cDNA, the probe was transferred to a Microcon YM-30 filter and centrifuged at 13,000 rcf for 6 min at RT. The spin column was inverted in a new collection tube and centrifuged at 13,000 rcf for 2 min at RT. The eluted probe volume was adjusted to 18.6 ï?l with nuclease free water and the following were added: 4 ï?l of yeast tRNA (10 ï?g/ï?l, Invitrogen, Carlsbad, CA), 4.9 ï?l of 20X SSC and 0.84 ï?l of 10% SDS. The probe was denatured at 100 Co for 3 min and centrifuged at 13,000 rcf for 45 sec. The probe was added directly to the microarray and a cover slip was added. Slides were hybridized overnight in DIE-TECH 1 or 5 slide hybridization chambers in a 65 Co water bath. After hybridization, cover slips were removed by incubation in 2x SSC / 0.05% SDS. Slides were then washed in 2x SSC / 0.05% SDS for 5 min and 0.2x SSC / 0.05% SDS for five minutes. Slides were then washed in 0.2x SSC for 10 sec and centrifuged dry at 500 rpm for 5 min. Measurement data and specifications: â?¢ Type of scanning hardware and software used: Microarrays were scanned using a GenePix 4000B scanner (Axon Instruments, Union City, CA). â?¢ Type of image analysis software used: Images were gridded and spots were quantified using GenePix Pro 4.0 software (Axon Instruments, Union City, CA). â?¢ A description of the measurements produced by the image-analysis software and a description of which measurements were used in the analysis: The measurements made by GenePix Pro 4.0 are described in the sample files. For all hybridizations, the log2 normalized Median of Ratios (as described below) was used. â?¢ Data selection and transformation procedures: Arrays were auto-gridded by GenePix 4.0. Features flagged by GenePix as not found during grid
2010-06-05 | E-GEOD-6099 | biostudies-arrayexpress
Project description:100 islets from wildtype and islet beta-cell Ins1Cre/+ ; Cpefl/fl mice were pooled and processed for top-down proteomic analysis. Briefly, homogenization buffer (8 M urea, 100 mM ammonium bicarbonate [ABC], 5 mM ethylenediaminetetraacetic acid [EDTA], 1 mM phenylmethylsulfonyl fluoride [PMSF]) was added to each sample before vortexing for 10 sec to resuspend islets followed by sonication in a water bath for 5 min at room temperature (rt). Reduction was accomplished through addition of 14 uL of 0.5 M tris(2-carboxyethyl)phosphine (TCEP) with incubation at rt for 2 h within a ThermoMixer (ThermoFisher) set at 1,200 RPM. This was followed by alkylation using 20 uL of 0.5 M iodoacetamide (IAA) and incubation for 30 min at rt in complete darkness at 1,200 RPM. The reaction was quenched through addition of 50 uL of dithiothreitol (DTT) before clarification of samples with 15 min centrifugation at 18,000 RCF at 10 deg C. The resulting supernatant was added to a 3 K MWCO Amicon Ultra 0.5 mL centrifugal filter (MilliporeSigma) and centrifuged at 14,000 RCF for 60 min at 10 deg C. Samples were analyzed using a Waters NanoACQUITY UPLC system with mobile phases consisting of 0.2% FA in H2O (Mobile Phase A) and 0.2% FA in ACN (Mobile Phase B). Both trapping-precolumn (150 um i.d., 5-cm length) and analytical column (100 um i.d., 50-cm length) were slurry-packed with C2 packing material (5 um and 3 um for trap/analytical respectively, 300 Angstrom, Separation Methods Technology). Samples were loaded into a 10 uL loop, corresponding to 400 ng of loaded material, and injected into the trapping column with an isocratic flow of 1% B at 5 uL/min over 15 min for desalting. Separation was performed with a 1% to 50% B gradient over 140 min at 300 nL/min. For MS/MS analysis of proteins, the NanoACQUITY system was coupled to a Thermo Scientific Orbitrap Fusion Lumos Tribrid mass spectrometer equipped with the FAIMS Pro interface.
2023-06-04 | MSV000092097 | MassIVE
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
Project description:Some molecular and cellular mechanisms of fertilization are still not completely described. The role of the acrosomal matrix (AM), the particulate compartment within the acrosome, is one of them. Here, we proposed that amyloids, highly ordered protein aggregates, by their physical and chemical properties could contribute to AM roles in fertilization. Purified AM were exposed to a two-step extraction to sequentially strip off soluble proteins. The remaining insoluble material (core) was subjected to a mass spectrometry analysis. Preparation of samples for MS analysis: Three different approaches were used to optimize identification of peptides in the AM core. For in-gel digestion, core samples were resuspended in 13.2mM SA pH3 containing 8M urea and 100 mM DTT and incubated for 1 hr at RT. Proteins were separated on a hand casted 12% polyacrylamide Tris-glycine gel. After silver staining, visible bands were cut from the gel, destained and washed with ddH2O (2 X 5 min) then with 50% ethanol (2 X 5 min) before stored at -20 degrees C. Gel pieces were tryptically digested in 25mM triethylammonium bicarbonate buffer at 37 degrees C overnight with trypsin. For in-solution digestion, core samples were resuspended in 13.2mM SA pH3/ 8M urea/ 100mM DTT and incubated for 1 h at RT followed by 15 min at 70 degrees C. Iodoacetamide was added to 10mM and proteins were alkylated by incubation for 15 min at RT in the dark. Samples were added to a pre-rinsed spin filter and centrifuged at 14,000 X g. Samples were washed with 9M urea then with 25mM ammonium bicarbonate. Samples were digested with trypsin in 25mM ammonium bicarbonate overnight. After digestion, samples were spin at 14,000 X g and washed 2 times with 25mM ammonium bicarbonate. The retentate was transferred to a new tube and air dried. For on-membrane digestion, the samples were dotted on nitrocellulose membrane and digested by trypsin. Briefly, core samples were resuspended and treated as for in-solution digestion. Then, samples were dotted by gravity on the membrane. Wells were rinsed with 20mM SA pH3 followed by TBS. Dots were cut and air-dried. After the protein digestion with trypsin in 25mM ammonium bicarbonate the membranes were dissolved with acetone and the precipitated peptides were air-dried. All digested peptides were reconstituted in 2% acetonitrile/ 0.1% formic acid for MS analysis. MS data acquisition: Protein identification by liquid chromatography tandem mass spectrometry (LCMS/MS) analysis of peptides was performed using an LTQ Orbitrap Velos MS interfaced with a 2D nanoLC system. Protein and Peptide Identification: MS/MS spectra were extracted using the ProteoWizard Toolkit. The spectra were analyzed using the GPM Manager with X!Tandem to search against a home made mouse database containing 213,054 nonredundant protein sequences created by using mouse sequences from Ensembl database (files Mus_musculus.GRCm38.73.pep.all & Mus_musculus.GRCm38.73.pep.abinitio) and from NCBI database (file nr downloaded on 09/19/2013) . Search was performed using fully tryptic enzyme specificity (See deposited MS data for details). Peptides and proteins that have an expectation value of log10 (e) <= -2 were included in the results. Curated results were obtained by keeping only proteins with at least one mouse-specific matching peptide (peptide match = 100% identities and 100% coverage on a unique mouse protein and <100% identities and/or <100% coverage on human proteins). In addition, trypsin-like proteins were kept if at least one peptide was not matching on exogenous pig trypsins.
2014-05-07 | PXD000592 | Pride