Details

Autor(en) / Beteiligte

• Kotrba, Pavel
• Ruml, Tomas

Titel

Surface Display of Metal Fixation Motifs of Bacterial P1-Type ATPases Specifically Promotes Biosorption of Pb²⁺ by Saccharomyces cerevisiae

Ist Teil von

• Applied and Environmental Microbiology, 2010-04, Vol.76 (8), p.2615-2622

Ort / Verlag

Washington, DC: American Society for Microbiology

Erscheinungsjahr

2010

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Biosorption of metal ions may take place by different passive metal-sequestering processes such as ion exchange, complexation, physical entrapment, and inorganic microprecipitation or by a combination of these. To improve the biosorption capacity of the potential yeast biosorbent, short metal-binding NP peptides (harboring the CXXEE metal fixation motif of the bacterial Pb²⁺-transporting P1-type ATPases) were efficiently displayed and covalently anchored to the cell wall of Saccharomyces cerevisiae. These were fusions to the carboxyl-terminal part of the sexual adhesion glycoprotein α-agglutinin (AGα1Cp). Compared to yeast cells displaying the anchoring domain only, those having a surface display of NP peptides multiplied their Pb²⁺ biosorption capacity from solutions containing a 75 to 300 μM concentration of the metal ion up to 5-fold. The S-type Pb²⁺ biosorption isotherms, plus the presence of electron-dense deposits (with an average size of 80 by 240 nm, observed by transmission electron microscopy) strongly suggested that the improved biosorption potential of NP-displaying cells is due to the onset of microprecipitation of Pb species on the modified cell wall. The power of an improved capacity for Pb biosorption was also retained by the isolated cell walls containing NP peptides. Their Pb²⁺ biosorption property was insensitive to the presence of a 3-fold molar excess of either Cd²⁺ or Zn²⁺. These results suggest that the biosorption mechanism can be specifically upgraded with microprecipitation by the engineering of the biosorbent with an eligible metal-binding peptide.