Peer-Reviewed Journal Details
Mandatory Fields
Drogaris, P,Le Blanc, JCY,Fitzgerald, JE,Lowndes, NF,Verreault, A,Thibault, P
2009
August
Analytical Chemistry
Enhanced Protein Detection Using a Trapping Mode on a Hybrid Quadrupole Linear Ion Trap (Q-Trap)
Published
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Optional Fields
NUCLEOSOME CORE PARTICLES TOP-DOWN CHARACTERIZATION TANDEM MASS-SPECTROMETRY INTACT PROTEINS IDENTIFICATION PURIFICATION CAPABILITIES PROTEOMICS
81
6300
6309
A novel method to improve the detection of protein ions using a linear ion trap mass spectrometer is presented. A scan function combining charge separation with segmented transmission of multiply charged ions was developed to enhance the sensitivity and resolution of the linear ion trap for the nanoLC-MS analysis of intact proteins. The analytical benefits of the present method are particularly apparent in protein analyses, where the increased proportion of multiply charged ions can exacerbate space-charge effects and compromise the dynamic range of the linear ion trap instrument. The enhanced ion storage and charge separation capabilities of our targeted and enhanced multiply charged scan mode provided a 4-fold increase in signal-to-noise and 5-fold increase in resolution, thus enabling the detection of closely related protein isoforms. The application of this method is demonstrated for low femtomole detection of protein standards and nuclear extracts enriched in histone proteins. The enhanced resolution of this scan mode also enabled us to monitor subtle changes in the methylation of a subpopulation of histone H3 that occurs in chicken DT40 cells lacking specific methyltransferase activity. The extent of the fold change and PTM site localization was performed using predictive software tools and targeted multiple reaction monitoring analysis of histone peptides. Monomethylation of Lys 79 in histone H3 (H3K79me1) was down regulated by 240-fold in methyltransferase deficient cells.
DOI 10.1021/ac9004259
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