Chalkophore-mediated respiratory oxidase flexibility controls <i>M. tuberculosis</i> virulence.

Abstract

Oxidative phosphorylation has emerged as a critical therapeutic vulnerability of <i>M. tuberculosis</i> (<i>Mtb</i>). However, it is unknown how intracellular bacterial pathogens such as <i>Mtb</i> maintain respiration during infection despite the chemical effectors of host immunity. <i>Mtb</i> synthesizes diisonitrile lipopeptides that tightly chelate copper, but the role of these chalkophores in host-pathogen interactions is also unknown. We demonstrate that <i>M. tuberculosis</i> chalkophores maintain the function of the heme-copper <i>bcc:aa₃</i> respiratory supercomplex under copper limitation. Chalkophore deficiency impairs <i>Mtb</i> survival, respiration to oxygen, and ATP production under copper deprivation in culture, effects that are exacerbated by loss of the heme-dependent Cytochrome BD respiratory oxidase. Our genetic analyses indicate that the maintenance of respiration is the major cellular target of chalkophore-mediated copper acquisition. <i>M. tuberculosis</i> lacking chalkophore biosynthesis is attenuated in mice, a phenotype that is also severely exacerbated by loss of the CytBD respiratory oxidase. We find that the host immune pressure that attenuates chalkophore-deficient <i>Mtb</i> is independent of adaptive immunity and neutrophils. These data demonstrate that chalkophores counter host-inflicted copper deprivation and highlight a multilayered system by which <i>M. tuberculosis</i> maintains respiration during infection.