Identification of secreted proteins of Mycobacterium tuberculosis by a bioinformatic approach

Proteins secreted by Mycobacterium tuberculosis are usually targets of immu ne responses in the infected host. Here we describe a search for secreted p roteins that combined the use of bioinformatics and phoA' fusion technology . The 3,924 proteins deduced from the ill. tuberculosis genome were analyze d with several computer programs. We identified 52 proteins carrying an NH2 -terminal secretory signal peptide but lacking additional membrane-anchorin g moieties, Of these 52 proteins-the TM1 subgroup-only 7 had been previousl y reported to be secreted proteins. Our predictions were confirmed in 9 of 10 TM1 genes that were fused to Escherichia coil phoA, a marker of subcellu lar localization. These findings demonstrate that the systematic computer s earch described in this work identified secreted proteins of ill, tuberculo sis with high efficiency and 90% accuracy.