Application of a subtractive genomics approach for in silico identification and characterization of novel drug targets in Mycobacterium tuberculosis F11.

Extensive dead ends or host toxicity of the conventional approaches of drug development can be avoided by applying the in silico subtractive genomics approach in the designing of potential drug target against bacterial diseases. This study utilizes the advanced in silico genome subtraction methodology to design potential and pathogen specific drug targets against Mycobacterium tuberculosis, causal agent of deadly tuberculosis. The whole proteome of Mycobacterium tuberculosis F11 containing 3941 proteins have been analyzed through a series of subtraction methodologies to remove paralogous proteins and proteins that show extensive homology with human. The subsequent exclusion of these proteins ensured the absence of host cytotoxicity and cross reaction in the identified drug targets. The high stringency (expectation value 10(-100)) analysis of the remaining 2935 proteins against database of essential genes resulted in 274 proteins to be essential for Mycobacterium tuberculosis F11. Comparative analysis of the metabolic pathways of human and Mycobacterium tuberculosis F11 by KAAS at the KEGG server sorted out 20 unique metabolic pathways in Mycobacterium tuberculosis F11 that involve the participation of 30 essential proteins. Subcellular localization analysis of these 30 essential proteins revealed 7 proteins with outer membrane potentialities. All these proteins can be used as a potential therapeutic target against Mycobacterium tuberculosis F11 infection. 66 of the 274 essential proteins were uncharacterized (described as hypothetical) and functional classification of these proteins showed that they belonged to a wide variety of protein classes including zinc binding proteins, transferases, transmembrane proteins, other metal ion binding proteins, oxidoreductase, and primary active transporters etc. 2D and 3D structures of these 15 membrane associated proteins were predicted using PRED-TMBB and homology modeling by Swiss model workspace respectively. The identified drug targets are expected to be of great potential for designing novel anti-tuberculosis drugs and further screening of the compounds against these newly targets may result in discovery of novel therapeutic compounds that can be effective against Mycobacterium tuberculosis.