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A novel iron‐ and copper‐binding protein in the L yme disease spirochaete
Author(s) -
Wang Peng,
Lutton Anthony,
Olesik John,
Vali Hojatollah,
Li Xin
Publication year - 2012
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12068
Subject(s) - biology , spirochaete , metallothionein , copper , copper toxicity , microbiology and biotechnology , pathogen , mutant , biochemistry , borrelia burgdorferi , bacteria , genetics , gene , chemistry , organic chemistry , antibody
Summary Iron and copper are transition metals that can be toxic to cells due to their abilities to react with peroxide to generate hydroxyl radical. Ferritins and metallothioneins are known to sequester intracellular iron and copper respectively. The L yme disease pathogen B orrelia burgdorferi does not require iron, but its genome encodes a ferritin‐like D ps ( D NA ‐binding p rotein from s tarved bacteria) molecule, which has been shown to be important for the spirochaete's persistence in the tick and subsequent transmission to a new host. Here, we show that the c arboxyl‐terminal c ysteine‐ r ich ( CCR ) domain of this protein functions as a copper‐binding metallothionein. This novel fusion between D ps and metallothionein is unique to and conserved in all B orrelia species. We term this molecule BicA for B orrelia i ron‐ and c opper‐binding protein A . An isogenic mutant lacking BicA had significantly reduced levels of iron and copper and was more sensitive to iron and copper toxicity than its parental strain. Supplementation of the medium with iron or copper rendered the spirochaete more susceptible to peroxide killing. These data suggest that an important function of BicA is to detoxify excess iron and copper the spirochaete may encounter during its natural life cycle through a tick vector and a vertebrate host.