Identification of Secreted Proteins of Mycobacterium tuberculosis by a Bioinformatic Approach

Abstract

ABSTRACT Proteins secreted by Mycobacterium tuberculosis are usually targets of immune responses in the infected host. Here we describe a search for secreted proteins that combined the use of bioinformatics and phoA ′ fusion technology. The 3,924 proteins deduced from the M. tuberculosis genome were analyzed with several computer programs. We identified 52 proteins carrying an NH 2 -terminal secretory signal peptide but lacking additional membrane-anchoring moieties. Of these 52 proteins—the TM1 subgroup—only 7 had been previously reported to be secreted proteins. Our predictions were confirmed in 9 of 10 TM1 genes that were fused to Escherichia coli phoA ′, a marker of subcellular localization. These findings demonstrate that the systematic computer search described in this work identified secreted proteins of M. tuberculosis with high efficiency and 90% accuracy.