title: Synthesis of S-layer conjugates and evaluation of their modifiability as a tool for the functionalization and patterning of technical surfaces.
abstract: Chemical functional groups of surface layer (S-layer) proteins were chemically modified in order to evaluate the potential of S-layer proteins for the introduction of functional molecules. S-layer proteins are structure proteins that self-assemble into regular arrays on surfaces. One general feature of S-layer proteins is their high amount of carboxylic and amino groups. These groups are potential targets for linking functional molecules, thus producing reactive surfaces. In this work, these groups were conjugated with the amino acid tryptophan. In another approach, SH-groups were chemically inserted in order to extend the spectrum of modifiable groups. The amount of modifiable carboxylic groups was further evaluated by potentiometric titration in order to evaluate the potential efficiency of S-layer proteins to work as matrix for bioconjugations. The results proved that S-layer proteins can work as effective matrices for the conjugation of different molecules. The advantage of using chemical modification methods over genetic methods lies in its versatile usage enabling the attachment of biomolecules, as well as fluorescent dyes and inorganic molecules. Together with their self-assembling properties, S-layer proteins are suitable as targets for bioconjugates, thus enabling a nanostructuring and bio-functionalization of surfaces, which can be used for different applications like biosensors, filter materials, or (bio)catalytic surfaces.
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz-Institute Freiberg for Resource Technology, Halsbruecker Strasse 34, 09533 Freiberg, Germany. u.weinert@hzdr.de.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Weinert
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz-Institute Freiberg for Resource Technology, Halsbruecker Strasse 34, 09533 Freiberg, Germany. k.pollmann@hzdr.de.
authors.forename: Katrin
authors.initials: K
authors.lastname: Pollmann
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany. a.barkleit@hzdr.de.
authors.forename: Astrid
authors.initials: A
authors.lastname: Barkleit
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz-Institute Freiberg for Resource Technology, Halsbruecker Strasse 34, 09533 Freiberg, Germany. a.barkleit@hzdr.de.|Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany. a.barkleit@hzdr.de.
authors.forename: Manja
authors.initials: M
authors.lastname: Vogel
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz-Institute Freiberg for Resource Technology, Halsbruecker Strasse 34, 09533 Freiberg, Germany. t.guenther@hzdr.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Günther
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz-Institute Freiberg for Resource Technology, Halsbruecker Strasse 34, 09533 Freiberg, Germany. a.barkleit@hzdr.de.|Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany. a.barkleit@hzdr.de.
authors.forename: Johannes
authors.initials: J
authors.lastname: Raff
mesh_terms: D001406:Bacillaceae / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification; D055162:Biocatalysis; D015374:Biosensing Techniques; D005456:Fluorescent Dyes / Q000737:chemistry; D055767:Immobilized Proteins / Q000737:chemistry* / Q000302:isolation & purification; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000302:isolation & purification; D036103:Nanotechnology / Q000379:methods; D011199:Potentiometry; D011485:Protein Binding; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013499:Surface Properties; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D005456:Fluorescent Dyes; D055767:Immobilized Proteins; D008562:Membrane Glycoproteins; C055764:S-layer proteins; D013438:Sulfhydryl Compounds; D014364:Tryptophan
keywords: EDC; bio-functionalization of surfaces; chemical modification; immobilization; modification rate; modified surface-layer proteins; potentiometric titration