Investigation of the ELP-Mediated Silicification-Based Protein Self-Immobilization Using an Acidic Target Enzyme

Elastin-like polypeptide: A novel titanification biomacromolecule for green and ultrafast synthesis of biotitania nanoparticles via biomimetic mineralization

Elastin-like polypeptides (ELPs), a temperature-responsive biological macromolecule, is used to develop a novel and eco-friendly strategy for biotitania synthesis. Three ELPs (V9F, KV8F, and K5V4F) are designed and overexpressed in E. coli. Then these recombinant ELPs are purified with high yields by using phase transition-based green ITC method. ELPs present the capabilities of ultrafast formation of biotitania within seconds. The specific activity of ELPs is significantly influenced by the number of lysine residues. K5V4F is the one with the highest specific activity of 56.90, which is 26.34 times higher than that of R5 peptide. Moreover, ELPs-mediated biomimetic titania mineralization can perform in a broad pH range (2.2 ≤ pH ≤ 10.8) at ambient temperatures, however, the optimum condition is near-neutral pH. The biotitania nanoparticles are evidenced to be as solid, spherical, and amorphous by SEM, TEM, and SAED analysis. Based on the unique temperature-responsiveness of ELPs and their excellent biomimetic mineralization abilities, this method may have great potentials to prepare smart biotitania nanomaterials for various application fields, such as biomedical engineering, biomanufacturing, and environmental remediation.

Magnetic silica-coated cutinase immobilized via ELPs biomimetic mineralization for efficient nano-PET degradation

The proliferation of nano-plastic particles (NPs) poses severe environmental hazards, urgently requiring effective biodegradation methods. Herein, a novel method was developed for degrading nano-PET (polyethylene terephthalate) using immobilized cutinases. Nano-PET particles were prepared using a straightforward method, and biocompatible elastin-like polypeptide-magnetic nanoparticles (ELPs-MNPs) were obtained as magnetic cores via biomimetic mineralization. Using one-pot synthesis with the cost-effective precursor tetraethoxysilane (TEOS), silica-coated magnetically immobilized ELPs-tagged cutinase (ET-C@SiO2@MNPs) were produced. ET-C@SiO2@MNPs showed rapid magnetic separation within 30 s, simplifying recovery and reuse. ET-C@SiO2@MNPs retained 86 % of their initial activity after 11 cycles and exhibited superior hydrolytic capabilities for nano-PET, producing 0.515 mM TPA after 2 h of hydrolysis, which was 96.6 % that of free enzymes. Leveraging ELPs biomimetic mineralization, this approach offers a sustainable and eco-friendly solution for PET-nanoplastic degradation, highlighting the potential of ET-C@SiO2@MNPs in effective nanoplastic waste management and contributing to environmental protection and sustainable development.

Biomimetic one-pot preparation of surface biofunctionalized silica-coated magnetic composites for dual enzyme oriented immobilization without pre-purification

Surface functioned magnetic silica particles are efficient carriers to achieve facilitated separation and recycling of biocatalysts. However, traditional methods of modifying magnetic silica particles required time-costly sequential coating and surface modification steps and toxic solvents. Herein, a green and efficient routine was proposed to prepare the surface modified silica-coated magnetic microspheres (SCEs@SiO₂ @Fe₃O₄) in one-pot. The elastin-like polypeptides (ELPs)-SpyCatcher chimera (SCEs) were purified by inverse transition cycling with high yield (275 mg/L) and incorporated into the magnetic silica spheres based on the biomimetic silicification capability of ELPs as proved by the EDS and SEM mapping. No SCEs leaked was observed within 48 h, indicating excellent stability in buffer. Then, the biofunctionalized carriers were used to purify and immobilize the target dual enzymes (xylanase-linker-SpyTag-linker-lichenase, bienzymes) directly from the crude cell lysis solution by the spontaneous isopeptide bond reaction between SpyCatcher and SpyTag. The immobilized bienzymes were sphere-like magnetic silica particles with uniform size, which had good magnetic responsiveness. The immobilization yield, immobilization efficiency and activity recovery for xylanase were 86%, 84 % and 72 %, while for lichenase was 92 %, 86 % and 79 %, respectively. Besides, the immobilized bienzymes showed good reusability (>60 %, 10 times for xylanase, >95 %, 8 times for lichenase). The SCEs modified silica-coated magnetic microspheres are expected to provide versatile platforms for single-step of purification and immobilization of multienzymes, offering great potentials in the field of biocatalysis.

Revealing the role of tunable amino acid residues in elastin-like polypeptides (ELPs)-mediated biomimetic silicification

Elastin-like polypeptides (ELPs) are attractive materials for the green preparation of silica nanoparticles via biomimetic silicification. However, the critical factors affecting the ELP-mediated silicification remain unclear. Herein, the role of tunable amino acid residues of ELPs in silicification was studied using three ELPs (ELPs[V9F-40], ELPs[KV8F-40], and ELPs[K5V4F-40]) and their fusion proteins (ELPs[V9F-40]-SpyCatcher, ELPs[KV8F-40]-SpyCatcher, and ELPs[K5V4F-40]-SpyCatcher) with different contents of lysine residues. Bioinformatics methods were employed for the first time to reveal the key physicochemical parameters correlated with silicification. The specific activity of ELPs was increased with the promotion of lysine content with a high correlation coefficient (R = 0.899). Furthermore, exogenous acidic protein SpyCatcher would hinder the interactions between the silica precursors and ELPs, leading to the significantly decrease in specific activity. The isoelectric point (pI) of ELPs presented the highest correlation to silicification with a coefficient of 0.963. The charges of the ELPs [K5V4F-40] at different pH were calculated based on the sequence or structure. Interestingly, the excellent correlation between charges based on structure and specific activity was obtained. Collectively, the novel methods developed here may pave a new way for rational design of ELPs or other peptides for efficient and green preparation of silica nanomaterials for biomedicine, biocatalysis, and biosensor.

A versatile tag for simple preparation of cutinase towards enhanced biodegradation of polyethylene terephthalate

Enzymatic degradation of polyethylene terephthalate (PET) suffered from challenges such as complex and costly enzyme preparation, difficult access to PET substrates, poor reusability of free enzymes and sometimes MHET inhibitions. Herein, we propose an "all-in-one" strategy to address these issues with a well-designed elastin-like polypeptides (ELPs) tag. The preparation of the ELPs-tagged cutinase (ET-C) was efficient and easy to scale up by centrifugation, with an activity recovery of 57.55 % and a yield of 160 mg/L. Besides, the activity of the ET-C was 1.3 and 1.66-fold higher in degrading PET micro- and macro-plastics compared to wild-type cutinase. The self-immobilized cutinase (ET-C@SiO₂) obtained by the ELPs-mediated biosilicification exhibited high loading capacity, activity, and thermostability and maintained 77.65 % of the original activity after 10 reuses. Interestingly, the product of the ET-C was TPA, whereas the wild-type was TPA and MHET. This is a simple way to release the intermediates inhibition compared with the existing methods. Our results demonstrated the feasibility of the versatile ELPs tag, which will pave an alternative economic way for scalable PET biodegradation.