Abstract
Intact actinomycetes and their cellular extracts were analyzed directly on a matrix-assisted laser desorption/ionization time-of-flight（MALDI-TOF）mass spectrometer. Experiments were designed to identify biomarkers from different genera of actinomycetes. A biomarker of 7026 ± 2 Da was detected in the mass spectra of three species that belong to the genus Microbispora. Another polypeptide of 7222 ± 1 Da was identified in two species of actinomycetes from the genus Dactylosporangium. After chromatography separations, the biomarkers from Microbispora and Dactylosporangium were subjected to protease digestion and ‘peptide mapping’ analysis. The results were used in database search. Furthermore, partial sequencing data were obtained by conventional Edman degradation and analyses of post source decay (PSD) and collision induced dissociation (CID) fragment ion spectra. From these analyses, we suggest that these biomarkers are cold shock proteins and mass spectrometry can provide a sensitive and accurate method for identifying microorganisms. Therefore, with mass spectrometric analysis, we hope to identify more cold shock proteins as biomarkers for classification of actinomycetes.