抄録
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is beginning to play an important role in rapid identification and classification of industrially useful or pathogenic bacteria. Instead of conventional mass spectral fingerprint approaches, MALDI-MS identification of bacteria using ca. 50 ribosomal subunit proteins as biomarkers has been proposed. In this bioinformatics-based method, the masses of ribosomal subunit proteins in bacterial lysates observed by MALDI-MS are compared with the calculated masses predicted from the amino acid sequences registered on protein databases such as Swiss-Prot. Therefore, taxonomic identification of bacteria at species level would be ideally performed. Considering the possible mismatch between the actual and calculated masses of the biomarkers, we further developed a highly reliable method applicable to bacterial classification at strain level by detailed characterization of expressed ribosomal subunit proteins of several bacteria. With our developed method using a verified mass list of expressed ribosomal proteins of genome-sequenced strains as a reference, bacterial samples isolated from soil could be successfully classified at strain level. As an application, detection of cross-contamination of culture collections was also described.
