TY - JOUR
T1 - Synergistic toxicity of copper and gold compounds in Cupriavidus metallidurans
AU - Wiesemann, Nicole
AU - Bütof, Lucy
AU - Herzberg, Martin
AU - Hause, Gerd
AU - Berthold, Lutz
AU - Etschmann, Barbara
AU - Brugger, Joël
AU - Martinez-Criado, Gema
AU - Dobritzsch, Dirk
AU - Baginsky, Sacha
AU - Reith, Frank
AU - Nies, Dietrich H.
PY - 2017/1/1
Y1 - 2017/1/1
N2 - The bacterium Cupriavidus metallidurans can reduce toxic gold(I/III) complexes and biomineralize them into metallic gold (Au) nanoparticles, thereby mediating the (trans)formation of Au nuggets. In Au-rich soils, most transition metals do not interfere with the resistance of this bacterium to toxic mobile Au complexes and can be removed from the cell by plasmid-encoded metal efflux systems. Copper is a noticeable exception: the presence of Au complexes and Cu ions results in synergistic toxicity, which is accompanied by an increased cytoplasmic Cu content and formation of Au nanoparticles in the periplasm. The periplasmic Cu-oxidase CopA was not essential for formation of the periplasmic Au nanoparticles. As shown with the purified and reconstituted Cu efflux system CupA, Au complexes block Cu dependent release of phosphate from ATP by CupA, indicating inhibition of Cu transport. Moreover, Cu resistance of Au-inhibited cells was similar to that of mutants carrying deletions in the genes for the Cu-exporting PIB1-type ATPases. Consequently, Au complexes inhibit export of cytoplasmic Cu ions, leading to an increased cellular Cu content and decreased Cu and Au resistance. Uncovering the biochemical mechanisms of synergistic Au and Cu toxicity in C. metallidurans explains the issues this bacterium has to face in auriferous environments, where it is an important contributor to the environmental Au cycle.
AB - The bacterium Cupriavidus metallidurans can reduce toxic gold(I/III) complexes and biomineralize them into metallic gold (Au) nanoparticles, thereby mediating the (trans)formation of Au nuggets. In Au-rich soils, most transition metals do not interfere with the resistance of this bacterium to toxic mobile Au complexes and can be removed from the cell by plasmid-encoded metal efflux systems. Copper is a noticeable exception: the presence of Au complexes and Cu ions results in synergistic toxicity, which is accompanied by an increased cytoplasmic Cu content and formation of Au nanoparticles in the periplasm. The periplasmic Cu-oxidase CopA was not essential for formation of the periplasmic Au nanoparticles. As shown with the purified and reconstituted Cu efflux system CupA, Au complexes block Cu dependent release of phosphate from ATP by CupA, indicating inhibition of Cu transport. Moreover, Cu resistance of Au-inhibited cells was similar to that of mutants carrying deletions in the genes for the Cu-exporting PIB1-type ATPases. Consequently, Au complexes inhibit export of cytoplasmic Cu ions, leading to an increased cellular Cu content and decreased Cu and Au resistance. Uncovering the biochemical mechanisms of synergistic Au and Cu toxicity in C. metallidurans explains the issues this bacterium has to face in auriferous environments, where it is an important contributor to the environmental Au cycle.
KW - Biomineralization
KW - Copper
KW - Cu-dependent oxidase
KW - Gold
KW - Toxicity
UR - http://www.scopus.com/inward/record.url?scp=85034078871&partnerID=8YFLogxK
U2 - 10.1128/AEM.01679-17
DO - 10.1128/AEM.01679-17
M3 - Article
C2 - 28939602
AN - SCOPUS:85034078871
VL - 83
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
SN - 0099-2240
IS - 23
M1 - e01679-17
ER -