The present invention relates to the design of the Antisense-oligonucleotide complementary to the specific region of peptide deformylase gene from Mycobacterium tuberculosis. The use of this Antisense-oligonucleotide on mycobacterial culture inhibits the production of the peptide deformylase enzyme by hybridizing within the region, which is found to be responsible for maintaining stability as well as retaining the functionality of the enzyme and thus in turn affecting the growth of the cells. This invention also establishes the essentiality of the peptide deformylase enzyme in mycobacteria and claims it as a drug target in this microorganism.