Among biomaterials, biofilm proteins occupy a great portion. They have many prominent properties such as mechanical strength, ability to be modified genetically and their stability against harsh physical and chemical conditions from their environment. Their high tendency to genetic modifications provides them wide application areas ranging from environmental pollution prevention to medical usage areas. Therefore, it is of crucial importance that biofilm proteins can handle different genetic modifications for a desired purpose of use.
In this thesis, we aimed to form complex structures of CsgA biofilm protein with three different functional groups. The functional groups we used are laccase type enzymes, i.e. CotA and YlmD, and a lectin, Griffithsin (GRFT). The complex formation between CsgA biofilm protein and the aforementioned functional groups is achieved with the help of an irreversible bond formed when SpyTag-SpyCatcher protein domains interact with each other. With the complexes we obtained from CsgA and CotA, YlmD enzymes we performed degradation of a fluoroquinolone type antibiotic, which is abundantly found in the natural water bodies causing antibiotic resistance. The degradation products of the antibiotic were assessed via LCMS-QTOF. We have also formed a complex from CsgA and GRFT in which we aimed to capture SARS-CoV-2 virus particles from aqueous media. We have checked the infectivity of SARS-CoV-2 virus after incubation with the complex we created.
In conclusion, CsgA biofilm protein can effectively be modified with various functional groups by making use of an irreversible chemical bond formed when a set of other proteins interact. The complex formed at the end can be used for different purposes such as pollutant degradation and virus capture. The complex system is prone to modifications with other functional groups for desired application areas.