Unlocking the proteomic information encoded in MALDI-TOF-MS data used for microbial identification and characterization

Authors: Fagerquist, Clifton - Keith

Submitted to: Expert Review of Proteomics
Publication Type: Review Article
Publication Acceptance Date: 11/12/2016
Publication Date: 1/1/2017
Citation: Fagerquist, C.K. 2017. Unlocking the proteomic information encoded in MALDI-TOF-MS data used for microbial identification and characterization. Expert Review of Proteomics. 14(1):97-107.

Interpretive Summary: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is increasingly utilized as a rapid technique to identify microorganisms including pathogenic bacteria. This approach relies upon obtaining a MS “fingerprint” or “signature” of a microorganism and with the help of pattern recognition algorithms to identify it from a database of reference strains. The actual peaks observed in such MS spectra are not identified nor is their identity considered particularly important by some practitioners. In consequence, little attention has been paid to the significant proteomic information contained in the peaks that collectively constitute the MS “fingerprint”. This review/perspective is intended to explore this topic in greater detail in the hopes that it may spur interest and further research in this area.

Technical Abstract: Introduction: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS)is increasingly utilized as a rapid technique to identify microorganisms including pathogenic bacteria. However, little attention has been paid to the significant proteomic information encoded in the MS peaks that collectively constitute the MS ‘fingerprint’. This review/perspective is intended to explore this topic in greater detail in the hopes that it may spur interest and further research in this area. Areas covered: This paper examines the recent literature on utilizing MALDI-TOF for bacterial identification. Critical works highlighting protein biomarker identification of bacteria, arguments for and against protein biomarker identification, proteomic approaches to biomarker identification, emergence of MALDI-TOF-TOF platforms and their use for top-down proteomic identification of bacterial proteins, protein denaturation and its effect on protein ion fragmentation, collision cross-sections and energy deposition during desorption/ionization are also explored. Expert commentary: MALDI-TOF and TOF-TOF mass spectrometry platforms will continue to provide chemical analyses that are rapid, cost-effective and high throughput. These instruments have proven their utility in the taxonomic identification of pathogenic bacteria at the genus and species level and are poised to more fully characterize these microorganisms to the benefit of clinical microbiology, food safety and other fields.