Secreted proteins (the secretome) of the Brucella may mediate important pathogen-host interactions, but such proteins are technically difficult to analyze. In the present study, we describe an approach to identify Brucella melitensis secreted proteins by using proteome analysis. TCA-acetone was used to recovery extracellular proteins from the culture of Brucella melitensis, and two-dimensional gel electrophoresis followed by mass spectrometry for protein resolution and identification. At last, 40 proteins were identified. These proteins included substrate-binding proteins of ABC transporters, outermembrane proteins and heat shock proteins. The identification of these secreted proteins provides important clues for the understanding of the molecular mechanism of Brucella and interesting candidates for the vaccine to treat or prevent Brucella infections.
