Project description:The product ion scans were acquired with a 2.0-unit isolation width and a normalized collision energy of 35 in an LTQ-Orbitrap Velos Pro MS spectrometer (Orbitrap Velos Pro, Thermo Fisher Scientific, US).
Project description:Pichia pastoris GS115 was cultured in YPD medium and protein were extracted and separated on SDS-PAGE followed by in-gel trypsin digestion. Protein were also digested in-solution using trypsin and fractionated using SCX and bRPLC. A total of 101 peptide fractions were analyzed on LTQ-Orbitrap Velos mass spectrometer. The raw data was searched using Mascot, Sequest and MS Amanda search algorithms against P. pastorisGS115 NCBI RefSeq database through Proteome Discoverer software suite.
Project description:The experiment consists of M.hyp 232 cultures digests analyzed on two mass specs, LTQ Velos Pro and LTQ FT Ultra LTQ Velos Pro: Six cell culture replicates of M.hyo 232 were hydrophobically separated using tree detergents: Digitonin, Tween, and SDS. Each francion, including the insoluble pellet, was trypsin digested and then cleaned using an SCX trap follwed by a RP trap to remove detergents. Each fraction was sepated using a Dionex U3000 splitless nanoflow system operating at 333 nl per minute using a gradient of 2% ACN to 50% ACN in 4 hours. Eluate was analyzed using an LTQ Velos Pro mass spectrometer with 20 MS/MS scans of the 20 most intense peaks from each MS scan. Dynamic exclusion was enable for 3 minutes for each m/z with a repeat count of 1. LTQ FT Ultra: Two cell pellets for high resolution analysis were lysed and trypsin digested. Digested peptides were dried, resuspended in 20 mM KH2PO4, 20% ACN, pH 3 (Buffer A) in 2.5 µL and transferred to low retention vials in preparation for separation using an Ultimate 3000 configured for 2D-LC. Each sample was loaded at 15 µl/min onto an SCX microtrap for the first dimension of separation, involving SCX steps of Buffer A + 0, 5, 10, 15, 20, 25, 30, 40, 50, 100, 250, 500, and 1000 mM KCl. For the second dimension of separation, each eluted salt step was desalted with an inline peptide microtrap with 2% ACN, 0.1% FA at 5 µl/min. Once desalted, the microtrap was switched into line with a fritless nano column (75µm x ~10cm) containing C18 media (5µ, 200 Å Magic, Michrom). Peptides were eluted using a gradient of 2% to 36% ACN, 0.1% FA at 350 nl/min over 60 min and electrospray ionized for analysis using an LTQ FT Ultra mass spectrometer. A survey scan m/z 350-1750 was acquired in the FT ICR cell (Resolution = 100,000 at m/z 400, with an accumulation target value of 1,000,000 ions). Up to the 6 most abundant ions (>3,000 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 seconds. Analysis: X!tandem searches were performed using the Mycoplasma hyopneumoniae strain 232 reference protein set from NCBI. The only difference between the searches for the LTQ Velos and LTQ FT was the precursor mass tolenance being set to +-1500ppm and +-24ppm respectively. Decoy searches were performed and the data filtered at e-value <= 0.01 with single peptide proteins discarded. These results are included in the submission as two tab-delimited text files.
Project description:To identify low abundance autocrine growth factors in CHO cell conditioned media, we utilized a label-free shotgun proteomics approach. CHO cell conditioned media were harvested from fed batch bioreactors and concentrated using methanol/chlorofrom precipitation. Proteins in the samples were then subjected to proteolysis with trypsin, and then subjected to primary fractionation using a SCX column, followed by RP liquid chromatography MS (LC-MS) with a LTQ Orbitrap Velos instrument using the data dependent acquisition (DDA) method. The MS system was set up and run with a method which enabled fast acquisitions of high quality peptide precursor and fragment ion data, with the desired precursor mass accuracy of ±5 ppm. For the LTQ Orbitrap Velos MS, the data-dependent MS/MS analytical workflow in positive ion mode was used. Each precursor survey scan (m/z: 300 to 1800) by the Orbitrap mass analyzer (resolution = 60,000 FWHM) was linked to 10 MS/MS events using the 2D ion trap CID approach, with dynamic ion exclusion set at 60 s. This value was determined based on the observed mean peptide chromatographic peak width. All other instrument parameters were set up according to the manufacturer’s suggested values for complex peptide samples. The nano-ESI source was fitted with a 30-µm stainless steel nano-bore emitter (Thermo Fisher Scientific) with 1.7 kV applied near the tip. Raw data files from the LTQ Orbitrap Velos MS were processed using the Proteome Discoverer 1.3 software (Thermo Fisher Scientific). The LC-MS data were searched against the human (Homo sapiens; UniProtKb, updated in August 2012, 45 848 entries), mouse (Mus musculus; UniProtKb, updated in August 2012, 31 528 entries) and chinese hamster (Cricetulus griceus; UniprotKb, updated in August 2012, 24 609 entries) protein databases using the Sequest search engine for the LTQ Orbitrap Velos LC-MS data, assuming tryptic digestion with precursor ions to fall within 10 ppm of projected m/z values and a fragment ion mass tolerance of 0.5 m/z. The specified search parameters were carbamidomethylation of cysteine as fixed modification, oxidation of methionine as dynamic modification and a maximum of two missed cleavage events. Reverse database searching resulted in a specific false discovery rate (FDR) of 1% at the peptide and protein level.
Project description:Soluble extra-cellular proteins and peptides from human and mouse stool were fractionated on a C-4 solid phase extraction cartidge, trypsin digested, C-18 clean up and identified with MS/MS on a LTQ-Velos Orbitrap. Data processing: The readRAW program was used to generate peak lists from the original data. All protein sequences were reversed and concatenated to the original forward-oriented proteins. Spectra were assigned to peptides using a semi-specific enzyme specificity with the Mascot search algorithm (version 2.3.01) using static carbamidomethylation of cysteines, differential oxidized methionines, 50ppm precursor mass tolerance, 2 miscleavages and 0.8Da fragment ion tolerance. Searched against a mouse or human database.