title: Bioaccumulation of heavy metals with protein fusions of metallothionein to bacterial OMPs.
abstract: In view of potential biotechnological applications, eukaryotic metallothioneins (MTs) have been expressed in Escherichia coli as fusions to membrane or membrane-associated proteins such as LamB, the peptidoglycan-associated lipoprotein protein (PAL) or a hybrid Lpp/OmpA carrier sequence. The use of different anchors enables the MT moiety to be targeted into various cell compartments thus bringing the metal-binding ability of the resulting hybrids to specific sites of the cell structure. To this end, both full-size and partial sequences of the human or mouse MTs have been genetically fused to: i) the permissive site 153 of the LamB sequence, which loops out the MT to the external medium; ii) the N-terminus of a PAL variant devoid of its N-terminal cystein, which targets expression of the fusion into the periplasm; and iii) the C-terminus of Lpp-OmpA, for anchoring the MT to the outer membrane protein as an N-terminal fusion. Each type of fusion presented a distinct behavior in terms of expression, stability and ability to endow E. coli cells an enhanced accumulation of Cd2+, in good correlation with the number of metal-binding centers contributed by the MT moiety of the fusions. The expression in vivo of metalloproteins bound to bacterial envelope structures opens a way to design biomass with specific metal-binding properties.
authors.affiliation: Departament de Genètica, Universitat de Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Valls
authors.forename: R
authors.initials: R
authors.lastname: González-Duarte
authors.forename: S
authors.initials: S
authors.lastname: Atrian
authors.forename: V
authors.initials: V
authors.lastname: De Lorenzo
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D060588:LIM Domain Proteins; D008074:Lipoproteins / Q000378:metabolism; D008668:Metallothionein / Q000378:metabolism*; D019216:Metals, Heavy / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D010457:Peptidoglycan / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011509:Proteoglycans; D011993:Recombinant Fusion Proteins
chemical_list: D001425:Bacterial Outer Membrane Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C031163:ExcC protein, E coli; D060588:LIM Domain Proteins; C103594:LPP protein, human; D008074:Lipoproteins; C491227:Lpp protein, mouse; D019216:Metals, Heavy; D010457:Peptidoglycan; D011506:Proteins; D011509:Proteoglycans; D011993:Recombinant Fusion Proteins; C069988:PplA protein, Legionella pneumophila; D008668:Metallothionein