title: Directed, strong, and reversible immobilization of proteins tagged with a β-trefoil lectin domain: a simple method to immobilize biomolecules on plain agarose matrixes.
abstract: A highly stable lipase from Geobacillus thermocatenolatus (BTL2) and the enhanced green fluorescent protein from Aquorea victoria (EGFP) were recombinantly produced N-terminally tagged to the lectin domain of the hemolytic pore-forming toxin LSLa from the mushroom  Laetiporus sulphureus . Such a domain (LSL(150)), recently described as a novel fusion tag, is based on a β-trefoil scaffold with two operative binding sites for galactose or galactose-containing derivatives. The fusion proteins herein analyzed have enabled us to characterize the binding mode of LSL(150) to polymeric and solid substrates such as agarose beads. The lectin-fusion proteins are able to be quantitatively bound to both cross-linked and non-cross-linked agarose matrixes in a very rapid manner, resulting in a surprisingly dynamic protein distribution inside the porous beads that evolves from heterogeneous to homogeneous along the postimmobilization time. Such dynamic distribution can be related to the reversible nature of the LSL(150)-agarose interaction. Furthermore, this latter interaction is temperature dependent since it is 4-fold stronger when the immobilization takes place at 25 °C than when it does at 4 °C. The strongest lectin-agarose interaction is also quite stable under a survey of different conditions such as high temperatures (up to 60 °C) or high organic solvent concentrations (up to 60% of acetonitrile). Notably, the use of cross-linked agarose would endow the system with more robustness due to its better mechanical properties compared to the noncross-linked one. The stability of the LSL(150)-agarose interaction would prevent protein leaching during the operation process unless high pH media are used. In summary, we believe that the LSL(150) lectin domain exhibits interesting structural features as an immobilization domain that makes it suitable to reversibly immobilize industrially relevant enzymes in very simple carriers as agarose.
authors.affiliation: Departamento de Biocatálisis, Instituto de Catálisis, CSIC, Campus UAM, Cantoblanco 28049, Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: López-Gallego
authors.forename: Ivan
authors.initials: I
authors.lastname: Acebrón
authors.forename: Jose Miguel
authors.initials: JM
authors.lastname: Mancheño
authors.forename: Sebastian
authors.initials: S
authors.lastname: Raja
authors.forename: M Pilar
authors.initials: MP
authors.lastname: Lillo
authors.forename: Jose Manuel
authors.initials: JM
authors.lastname: Guisán Seijas
mesh_terms: D000363:Agaricales; D001483:Base Sequence; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D037102:Lectins / Q000737:chemistry*; D008958:Models, Molecular; D011506:Proteins / Q000737:chemistry*; D012685:Sepharose / Q000737:chemistry*
chemical_list: D017931:DNA Primers; D037102:Lectins; D011506:Proteins; D012685:Sepharose