Inducible cysteine synthesis by CysK2 provides copper resistance in Mycobacterium tuberculosis.

CysK2-mediated cysteine biosynthesis is essential for copper resistance in Mycobacterium tuberculosis, with a single amino acid substitution in H37Rv impairing this function.

• Why it matters: Copper toxicity is a key component of the host immune response against Mycobacterium tuberculosis, but the mechanisms by which the bacteria resist copper stress are not fully understood, especially in different strains.
• What they did: The study examined the activity of CysK2, a cysteine synthase encoded in the copper-inducible RicR regulon, and identified that a mutation in H37Rv reduces its copper resistance, linking cysteine biosynthesis to copper stress mitigation.
• The result: This research demonstrates that cysteine biosynthesis via CysK2 promotes copper resistance in M. tuberculosis, suggesting new potential targets for therapeutic intervention against the pathogen.