Nitric oxide releases intracellular zinc from prokaryotic metallothionein in Escherichia coli.
Nitric oxide (NO) has a broad spectrum of signalling and regulatory functions and multiple molecular targets. Recently, the intrabacterial toxicity of NO and mechanisms for NO resistance have been intensively investigated. Here we report for the first time that NO elicits release of zinc from a bacterial protein. Using the zinc-responsive expression of zntA (encoding a Zn-exporting P-type ATPase) fused to lacZ, i.e. Phi(zntA-lacZ), to monitor intracellular zinc, and SmtA (the Synechococcus metallothionein) as zinc store, we have shown that the NO donors NOC-5 and NOC-7 elicit zinc ejection. No increase in Phi(zntA-lacZ) activity was observed in a zntR mutant, indicating the specificity of the zntA promoter response to zinc ions.
Department of Molecular Biology and Biotechnology, Firth Court, Western Bank, University of Sheffield, Sheffield, UK.
Marie R B
MR
Binet
Hugo
H
Cruz-Ramos
Jay
J
Laver
Martin N
MN
Hughes
Robert K
RK
Poole
D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D008668:Metallothionein / Q000378:metabolism; D009154:Mutation; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D015032:Zinc / Q000378:metabolism* / Q000502:physiology
D009569:Nitric Oxide; D008668:Metallothionein; D000251:Adenosine Triphosphatases; C109898:Zn(II)-translocating P-type ATPase; D015032:Zinc