Mycobacterium tuberculosis (Mtb) infects an estimated one third of the world's population, causing more deaths per year than any other infectious agent. Mtb resides within an immunocompetent host for years or decades, indicating that the bacteria are able to survive insults from the host immune system such as reactive oxygen or nitrogen species. Little is known about the mechanisms that the bacteria use to endure these stresses. My primary interest is the mechanism used by Mycobacterium tuberculosis (Mtb) to directly (or non-enzymatically) protect its DNA during latent infection. This protection against the defenses of the innate immune system could allow Mtb to survive within an immunocompetent host for years or decades. My research utilizes genetic, microscopic, microarray, and biochemical studies to determine the mechanisms utilized by dormant Mtb to protect its DNA against reactive oxygen and nitrogen species.