Characterization of pbt genes conferring increased Pb(2+) and Cd(2+) tolerance upon Achromobacter xylosoxidans A8

0422943 - ÚMG 2014 RIV FR eng J - Journal Article
Hložková, K. - Šuman, J. - Strnad, Hynek - Ruml, T. - Pačes, Václav - Kotrba, P.
Characterization of pbt genes conferring increased Pb(2+) and Cd(2+) tolerance upon Achromobacter xylosoxidans A8.
Research in Microbiology. Roč. 164, č. 10 (2013), s. 1009-1018. ISSN 0923-2508. E-ISSN 1769-7123
R&D Projects: GA MŠMT(CZ) 1M0520
Grant - others:GA ČR(CZ) GAP504/11/0484
Program: GA
Institutional support: RVO:68378050
Keywords : Achromobacter xylosoxidans * metal tolerance * lead * cadmium * zinc * P1-type ATPase * MerR family * transcriptional control
Subject RIV: EB - Genetics ; Molecular Biology
Impact factor: 2.826, year: 2013

The cluster of pbtTFYRABC genes is carried by plasmid pA81. Its elimination from Achromobacter xylosoxidans A8 resulted in increased sensitivity towards Pb(2+) and Cd(2+). Predicted pbtTRABC products share strong similarities with Pb(2+) uptake transporter PbrT, transcriptional regulator PbrR, metal efflux P1-ATPases PbrA and CadA, undecaprenyl pyrophosphatase PbrB and its signal peptidase PbrC from Cupriavidus metallidurans CH34. Expression of pbtABC or pbtA in a metal-sensitive Escherichia coli GG48 rendered the strain Pb(2+)-, Cd(2+)- and Zn(2+)-tolerant and caused decreased accumulation of the metal ions. Accumulation of Pb(2+), but not of Cd(2+) or Zn(2+), was promoted in E. coli expressing pbtT. Additional genes of the pbt cluster are pbtF and pbtY, which encode the cation diffusion facilitator (CDF)-like transporter and a putative fatty acid hydroxylase of unknown function, respectively. Expression of pbtF did not confer increased metal tolerance upon E. coli GG48, although the protein showed measurable Pb(2+)-efflux activity. Unlike the pbtT promoter, promoters of pbtABC, pbtF and pbtY contain features characteristic of promoters controlled by metal-responsive transcriptional regulators of the MerR family. Upregulation of pbtABC, pbtF and pbtY upon Pb(2+), Cd(2+) and Zn(2+) exposure was confirmed in wild-type Achromobacter xylosoxidans A8. Gel shift assays proved binding of purified PbtR to the respective promoters. Copyright 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
Permanent Link: http://hdl.handle.net/11104/0229172