Solubilization and aggregation control of silica-polymerizing enzyme fused with a removable soluble protein

Understanding the relationships between solubility, stability, and activity of silicatein

“…Silicatein aggregation is credited to the large, exposed hydrophobic patches of the protein, with intermolecular disulfide bridges providing a stabilizing effect. 29,30 Recombinant silicatein has four cysteine residues, two of which form a bridge with each other (C34, C76), and an additional two that are available to interact with other molecules (C43, C145), according to previous work by Gorlich, et al 2020 31 (Fig. 4).…”

“…Notably, this reaction yields approximately 0.02% recovery of silicon from precursor to product over a period of 24 hours, consistent with other works. 15,29 As by Curran et al , additional biomineralization assays were conducted with ceria ammonium nitrate (CAN) to yield nanoscopic ceric oxide. These experiments yielded visible precipitates after 24 hours, suggesting greater conversion than with native substrate silica (Table S3 and Fig.…”

“…In the case of TF-silicatein, the tendency for aggregation is diminished by other forces, with one possibility being the notable steric hindrance of TF as described by Ullers, et al and Hoffmann, et al 21,22 Disulfide bridges Silicatein aggregation is credited to the large, exposed hydrophobic patches of the protein, with intermolecular disulfide bridges providing a stabilizing effect. 29,30 Recombinant silicatein has four cysteine residues, two of which form a bridge with each other (C34, C76), and an additional two that are available to interact with other molecules (C43, C145), according to previous work by Gorlich, et al 2020 31 (Fig. 4).…”

“…16 To address this challenge, and facilitate a reactor-based nanoparticle synthesis process, the field has focused on identifying a soluble version of silicatein. Studies by Dakhili, et al (2017) and Oguri, et al (2021) explore the addition of several different solubility tags to silicatein, highlighting minor solubility improvements with the addition of Trigger Factor and ProS2, respectively. 15,17 These studies note that cleavage of the solubility tag results in massive aggregation and precipitation of wild-type silicatein.…”

Interfacial biosilica coating of chitosan gel using fusion silicatein to fabricate robust hybrid material for biomolecular applications

“…The biosilica synthesized by silicatein is amorphous and has a porous structure containing nano-silica aggregates. 21 The biocompatibility of biosilica synthesised by silicatein has been confirmed by many studies which are related to biomedical applications such as drug delivery, bone formation, immobilization of biomolecules and tissue engineering. [22][23][24][25] Furthermore, silicatein can be fused with polysaccharide-binding proteins, which exhibit a high affinity for polysaccharides, to be immobilised on the surface of hydrogels for highly efficient interfacial biocatalysts.…”