Tandem Mass Spectrometry of Intact Proteins for Characterization of Biomarkers from Bacillus cereus T Spores

• Published in: Analytical chemistry (Washington) Vol. 73; no. 23; pp. 5725 - 5731
• Main Authors: DEMIREV, Plamen A., RAMIREZ, Javier, FENSELAU, Catherine
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-12-2001
• Subjects: Amino Acid Sequence; Bacillus cereus - chemistry; Bacteria; Biological and medical sciences; Biomarkers; Chemistry; Databases, Protein; Fundamental and applied biological sciences. Psychology; Ions; Mass Spectrometry; Molecular and cellular biology; Molecular Sequence Data; Proteins; Spectrum analysis; Spores, Bacterial - chemistry
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac010672n

Intact protein biomarkers from Bacillus cereus T spores have been analyzed by high-resolution tandem Fourier transform ion cyclotron resonance mass spectrometry. Two techniques have been applied for excitation of the isolated multiply charged precursor ion species: sustained off-resonance irradiation/collisionally activated dissociation and electron capture dissociation. Fragmentation-derived sequence tags and BLAST sequence similarity proteome database searches allow unequivocal identification of the major biomarker protein with unprecedented specificity. Sequence-specific fragmentation patterns further confirm protein identification. Moreover, methodology combining accurate mass measurements of intact proteins with additional information contained in a proteome database permits tentative assignment of several other protein biomarkers isolated from the B. cereus T spores. We argue that approaches involving tandem MS of protein biomarkers, combined with bioinformatics, can drastically improve the specificity of individual microorganism identification, particularly in complex environments.