Location: Produce Safety and Microbiology ResearchTitle: MALDI-TOF-TOF tandem mass spectrometry (MS/MS) for rapid top-down proteomic identification of bacterial proteins and toxins
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/3/2018
Publication Date: 1/23/2018
Citation: Fagerquist, C.K. 2018. MALDI-TOF-TOF tandem mass spectrometry (MS/MS) for rapid top-down proteomic identification of bacterial proteins and toxins. Meeting Proceedings. In: Application to the Clinical Lab 2018. January 21-25, 2018, Palm Springs, CA.
Technical Abstract: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has found significant utility in the rapid identification of clinically important bacterial microorganisms. It is now in use worldwide in hospitals, central strain repositories/collections and research labs. Data analysis involves use of pattern recognition algorithms incorporated into software that rapidly identify/differentiate bacterial microorganisms by comparison of the MS “fingerprint” of an unknown microorganism to a database of known microorganisms. The ionized biomolecules that collectively constitute a MS “fingerprint” are not themselves identified by this approach, however the profile of ion peaks generated allows identification of the microorganism. The taxonomic resolution of this technique is dependent on the variability of the mass-to-charge of the biomolecule ions being detected across genus, species, sub-subspecies and strains. Beyond taxonomic identification, practitioners also need information about a bacterial strain such as its potential virulence (e.g. toxins) and antibiotic resistance factors. Although whole genome sequencing (WGS) can provide much of this information, it can only indicate which genes are present not whether they are expressed or under what conditions. MALDI-TOF-TOF tandem mass spectrometry (MS/MS), an extension of MALDI-TOF-MS, allows not just detection of ionized biomolecules but also isolation and fragmentation leading to identification of specific biomolecules thus providing information about pathogenicity or antimicrobial resistance. If the biomolecule is a protein, a top-down proteomic approach can leverage the ever-increasing amounts of genomic information from WGS by comparing MS/MS fragment ions to in silico fragment ions (derived from WGS) allowing identification of the protein as well as the source microorganism. This lecture will discuss in detail the technical issues involved in such an analysis.