title: Quantitative mass spectrometry for bacterial protein toxins--a sensitive, specific, high-throughput tool for detection and diagnosis.
abstract: Matrix-assisted laser-desorption time-of-flight (MALDI-TOF) mass spectrometry (MS) is a valuable high-throughput tool for peptide analysis. Liquid chromatography electrospray ionization (LC-ESI) tandem-MS provides sensitive and specific quantification of small molecules and peptides. The high analytic power of MS coupled with high-specificity substrates is ideally suited for detection and quantification of bacterial enzymatic activities. As specific examples of the MS applications in disease diagnosis and select agent detection, we describe recent advances in the analyses of two high profile protein toxin groups, the Bacillus anthracis toxins and the Clostridium botulinum neurotoxins. The two binary toxins produced by B. anthracis consist of protective antigen (PA) which combines with lethal factor (LF) and edema factor (EF), forming lethal toxin and edema toxin respectively. LF is a zinc-dependent endoprotease which hydrolyzes specific proteins involved in inflammation and immunity. EF is an adenylyl cyclase which converts ATP to cyclic-AMP. Toxin-specific enzyme activity for a strategically designed substrate, amplifies reaction products which are detected by MALDI-TOF-MS and LC-ESI-MS/MS. Pre-concentration/purification with toxin specific monoclonal antibodies provides additional specificity. These combined technologies have achieved high specificity, ultrasensitive detection and quantification of the anthrax toxins. We also describe potential applications to diseases of high public health impact, including Clostridium difficile glucosylating toxins and the Bordetella pertussis adenylyl cyclase.
authors.affiliation: Centers for Disease Control and Prevention, 4770 Buford Hwy, NE, Atlanta, GA 30341, USA. jbarr@cdc.gov
authors.forename: Anne E
authors.initials: AE
authors.lastname: Boyer
authors.forename: Maribel
authors.initials: M
authors.lastname: Gallegos-Candela
authors.forename: Renato C
authors.initials: RC
authors.lastname: Lins
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Kuklenyik
authors.forename: Adrian
authors.initials: A
authors.lastname: Woolfitt
authors.forename: Hercules
authors.initials: H
authors.lastname: Moura
authors.forename: Suzanne
authors.initials: S
authors.lastname: Kalb
authors.forename: Conrad P
authors.initials: CP
authors.lastname: Quinn
authors.forename: John R
authors.initials: JR
authors.lastname: Barr
mesh_terms: D000595:Amino Acid Sequence; D001408:Bacillus anthracis / Q000737:chemistry*; D001426:Bacterial Proteins / Q000032:analysis*; D057230:Limit of Detection; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D001426:Bacterial Proteins