DNA as the intracellular secondary target for antibacterial action of human neutrophil peptide-I against Mycobacterium tuberculosis H37Ra

The secondary intracellular target of human neutrophil peptide-1 has been e xamined in M. tuberculosis H37Ra. Binding studies with radioiodinated HNP-1 revealed biphasic equilibrium binding kinetics with respect to time. The m ajor site of HNP-1 binding was found to be plasma membrane/cell wall wherea s the cytosol appears to be a secondary site. Among the different macromole cules examined, maximum inhibition (75%) was observed in DNA biosynthesis d uring treatment with HNP-1. The interaction of HNP-1 with mycobacterial gen omic DNA on the basis of gel retardation assay revealed HNP-1 binding to DN A. These results indicate that HNP-1 has DNA as the secondary intracellular target for antibacterial action against mycobacteria.