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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Produce Safety and Microbiology Research » Research » Publications at this Location » Publication #255003
Title: Rapid Identification of Food-borne Pathogens by Top-Down Proteomics Using MALDI-TOF/TOF Mass Spectrometry

Author
item Fagerquist, Clifton - Keith

Submitted to: American Chemical Society Annual Meeting Symposium Proceedings
Publication Type: Book / Chapter
Publication Acceptance Date: 1/14/2011
Publication Date: 6/6/2011
Citation: Fagerquist, C.K. 2011. Rapid Identification of Food-borne Pathogens by Top-Down Proteomics Using MALDI-TOF/TOF Mass Spectrometry. In: Fenselau, C; Demirev, P.,editors. Rapid Characterization of Microorganisms by Mass Spectrometry. Washington D.C., American Chemistry Society Publications. American Chemical Society Symposium Series. 1065:99-120

Interpretive Summary: Rapid identification of bacterial microorganisms is particularly relevant to efforts to monitor the safety and security of domestically grown and imported foods. Mass spectrometry (MS) is increasingly utilized to identify and characterize bacterial microorganisms and in particular food-borne pathogens. Matrix-assisted laser desorption/ionization (MALDI) time-of-flight time-of-flight tandem mass spectrometry (TOF-TOF-MS/MS) has recently been shown to fragment small and modest-sized singly-charged protein ions (without prior protein digestion) to generate sequence-specific fragment ions. These sequence-specific fragment ions can be used for identification of the protein and, if the protein sequence is sufficiently unique, the source microorganism. Our group has developed web-based software for rapid top-down identification of protein biomarkers of bacterial microorganisms from sequence-specific fragment ions analyzed by MALDI-TOF-TOF-MS/MS. The software rapidly compares the mass-to-charge (m/z) of MS/MS fragment ions to the m/z of in silico fragment ions derived from hundreds of bacterial protein sequences that have the same molecular weight as the protein biomarker ion. We have identified several protein biomarkers from pathogenic and non-pathogenic E. coli using this top-down proteomic identification approach.

Technical Abstract: Rapid identification of bacterial microorganisms is particularly relevant to efforts to monitor the safety and security of domestically grown and imported foods. Mass spectrometry (MS) is increasingly utilized to identify and characterize bacterial microorganisms and in particular food-borne pathogens. Matrix-assisted laser desorption/ionization (MALDI) time-of-flight time-of-flight tandem mass spectrometry (TOF-TOF-MS/MS) has recently been shown to fragment small and modest-sized singly-charged protein ions (without prior protein digestion) to generate sequence-specific fragment ions. These sequence-specific fragment ions can be used for identification of the protein and, if the protein sequence is sufficiently unique, the source microorganism. Our group has developed web-based software for rapid top-down identification of protein biomarkers of bacterial microorganisms from sequence-specific fragment ions analyzed by MALDI-TOF-TOF-MS/MS. The software rapidly compares the mass-to-charge (m/z) of MS/MS fragment ions to the m/z of in silico fragment ions derived from hundreds of bacterial protein sequences that have the same molecular weight as the protein biomarker ion. We have identified several protein biomarkers from pathogenic and non-pathogenic E. coli using this top-down proteomic identification approach.