Identification of a copper-binding metallothionein in pathogenic mycobacteria. Academic Article uri icon



  • A screen of a genomic library from Mycobacterium tuberculosis (Mtb) identified a small, unannotated open reading frame (MT0196) that encodes a 4.9-kDa, cysteine-rich protein. Despite extensive nucleotide divergence, the amino acid sequence is highly conserved among mycobacteria that are pathogenic in vertebrate hosts. We synthesized the protein and found that it preferentially binds up to six Cu(I) ions in a solvent-shielded core. Copper, cadmium and compounds that generate nitric oxide or superoxide induced the gene's expression in Mtb up to 1,000-fold above normal expression. The native protein bound copper within Mtb and partially protected Mtb from copper toxicity. We propose that the product of the MT0196 gene be named mycobacterial metallothionein (MymT). To our knowledge, MymT is the first metallothionein of a Gram-positive bacterium with a demonstrated function.

publication date

  • August 24, 2008



  • Copper
  • Metallothionein
  • Mycobacterium tuberculosis


PubMed Central ID

  • PMC2749609

Scopus Document Identifier

  • 51949098115

Digital Object Identifier (DOI)

  • 10.1038/nchembio.109

PubMed ID

  • 18724363

Additional Document Info


  • 4


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