Threonine dehydratase couples L-cysteine metabolism to cadmium resistance in Pseudomonas stutzeri 273 through cadmium sulfide nanoparticle biomineralization

Cysteine is an amino acid containing sulfhydryl (-SH) group which is the basis of cysteine involved in sulfur metabolism and heavy metal detoxification in microorganisms. Here, we demonstrate that adding L-cysteine significantly improves the cadmium resistance and removal ability of Pseudomonas stutzeri 273. Threonine dehydratase (TSD) connects L-cysteine metabolism and cadmium resistance through CdS nanoparticle biomineralization with the ability of catalyzing L-cysteine desulfuration and H2S generation in P. stutzeri 273. Gene knockout of TSD in P. stutzeri 273 results in the decrease of L-cysteine and cadmium resistance, decline of H2S generation, and reduction of CdS biosynthesis ability.