d × 360 μm o d column packed with 11 cm AQUA C18 for a single d

d. × 360 μm o.d. column packed with 11 cm AQUA C18 for a single dimension of capillary HPLC/tandem MS analysis. After 20 min of flushing with 5% acetonitrile, peptides were

eluted by an acetonitrile gradient (5–12% B in 1 min, hold 9 min, 12–40% B in 50 min, 40–80% B in PF477736 datasheet 1 min, hold 10 min, 80–5% B in 5 min, hold 14 min). The MS1 scan range for all samples was 400–2000 m/z. Each MS1 scan was followed by 10 MS2 scans in a data dependent manner for the 10 most intense ions in the MS1 scan. Default parameters under Xcalibur 1.4 data acquisition software (Thermo Fisher) were used, with the exception of an isolation width of 3.0 m/z units and a normalized collision energy of 40%. Data processing and protein identification Raw data were searched by SEQUEST [34] against a FASTA protein ORF database consisting

of the Ver. 3.1 curation of P. gingivalis W83 (2006, TIGR-CMR [47]), S. Eltanexor supplier gordonii Challis NCTC7868 (2007, TIGR-CMR [48], F. nucleatum ATCC 25586 (2002, TIGR-CMR [49]), bovine (2005, UC Santa Cruz), nrdb human subset (NCBI, as provided with Thermo Bafilomycin A1 clinical trial Bioworks ver. 3.3) and the MGC (Mammalian Gene collection, 2004 curation, NIH-NCI [50]) concatenated with the reversed sequences. After data processing, the genome sequence for strain 33277 became available [31] and the data were subsequently cross-referenced to PGN numbers from the 33277 specific FASTA database provided by LANL (personal communication with G. Xie). Although Naito et al. [31] reported extensive genome re-arrangements between W83 and ATCC 33277, the actual protein amino acid sequences are sufficiently similar across the proteome that the use of a database based on W83 was not expected to greatly impact the analysis. Our proteomic methods are not sensitive

to genome re-arrangements, only to changes in amino acid sequence for a given protein. The reversed sequences were used for purposes of calculating a peptide level qualitative FDR using the published method [51, 52]. The SEQUEST peptide level search results were filtered and grouped by protein using DTASelect [53], then input into a FileMaker script developed in-house [32, 33] for further processing. The DTASelect Ver. 1.9 filter parameters were: peptides triclocarban were fully tryptic; ΔCn/Xcorr values for different peptide charge States were 0.08/1.9 for +1, 0.08/2.0 for + 2, and 0.08/3.3 for +3; all spectra detected for each sequence were retained (t = 0). Only peptides that were unique to a given ORF were used in the calculations, ignoring tryptic fragments that were common to more than one ORF or more than one organism, or both. In practice this had the consequence of reducing our sampling depth from what we have achieved with single organism studies [27, 32, 33], because the gene sequence overlap among the three organisms is significant. A bioinformatic analysis (data not shown) of inferred protein sequence overlaps between P.

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