Shielding against Unfolding by Embedding Enzymes in Metal–Organic Frameworks via a de Novo Approach

Abstract

We show that an enzyme maintains its biological function under a wider range of conditions after being embedded in metal-organic framework (MOF) microcrystals via a de novo approach. This enhanced stability arises from confinement of the enzyme molecules in the mesoporous cavities in the MOFs, which reduces the structural mobility of enzyme molecules. We embedded catalase (CAT) into zeolitic imidazolate frameworks (ZIF-90 and ZIF-8), and then exposed both embedded CAT and free CAT to a denature reagent (i.e., urea) and high temperatures (i.e., 80 °C). The embedded CAT maintains its biological function in the decomposition of hydrogen peroxide even when exposed to 6 M urea and 80 °C, with apparent rate constants k (s) of 1.30 × 10 and 1.05 × 10, respectively, while free CAT shows undetectable activity. A fluorescence spectroscopy study shows that the structural conformation of the embedded CAT changes less under these denaturing conditions than free CAT.

Ultrarobust Biochips with Metal–Organic Framework Coating for Point-of-Care Diagnosis

“…It should be noted that the preservation mechanism of ZIF-8 coating against DMF or protease exposure is different, considering that the DMF can penetrate and move through the ZIF-8 pores 62 , while the protease is too large to enter the pores. 41 Hence, ZIF-8 encapsulation confines the structure and functional degradation of antibody due to the presence of DMF, whereas protease is shielded by the ZIF-8 coating.…”

Molecular Vise Approach to Create Metal‐Binding Sites in MOFs and Detection of Biomarkers

“…[5] One of the remaining challenges was to decipher the spatial arrangement of these functional components. Thet hickness of each slice is about 90 nm, and the resolution within the slice is about 180 nm according to the limit by the wavelength of the incident light [l = 405 nm, d = l/(2NA)], [8] corresponding to 45 and 65 unit cells along and perpendicular to [101] direction, respectively ( Figure 2E and F). Thet hickness of each slice is about 90 nm, and the resolution within the slice is about 180 nm according to the limit by the wavelength of the incident light [l = 405 nm, d = l/(2NA)], [8] corresponding to 45 and 65 unit cells along and perpendicular to [101] direction, respectively ( Figure 2E and F).…”

Synthesis of patterned enzyme–metal–organic framework composites by ink-jet printing

“…The focus of MOF applications is gas storage, separation, sensing, and catalysis (Furukawa et al 2013;Hayashi et al 2007;Sumida et al 2011;Zhou et al 2012). Moreover, MOFs also have shown great potentials in hosting biomolecules such as enzyme (or protein), explored by pioneering work from several groups in recent years (Lykourinou et al 2011;Chen et al 2012;Deng et al 2012;Lyu et al 2014;Shieh et al 2015;Liang et al 2015a;Feng et al 2015;Li et al 2016a, b, c;Lian et al 2016Lian et al , 2017Liao et al 2017;Zhang et al 2017;Wu et al 2015a, b;Hou and Ge 2017). The rigid but porous structure of MOFs makes them ideal for immobilizing flexible protein molecules to increase the overall structural stability of protein.…”

“…The rigid but porous structure of MOFs makes them ideal for immobilizing flexible protein molecules to increase the overall structural stability of protein. Benefited from the protection effect of MOF scaffolds, the incorporated enzyme can resist to various harsh environments that are harmful to fragile native enzyme, (Shieh et al 2015;Liang et al 2015a;Feng et al 2015) even at protein-denaturing conditions (Liao et al 2017;Wu et al 2017). The enhanced stability makes enzyme-MOF composites promising for industrial and biomedical applications such as biocatalysis at harsh conditions (Lykourinou et al 2011;Feng et al 2015;He et al 2016), enzymatic degradation of nerve agents, (Li et al 2016a, b) stabilizing tobacco mosaic virus (Lian et al 2016), and increasing sensitivity of biosensors (Lyu et al 2014;Zhang et al 2017).…”

“…By chemical reactions between amino acids of enzyme and functional groups of pre-synthesized MOFs, enzyme molecules were attached on the surface of MOFs (Jung et al 2011;Shih et al 2012). Alternatively, another strategy is in situ one-pot synthesis of enzyme-MOF composites directly from enzyme, metal ions, and organic ligands in solution, which has been investigated by several groups (Lyu et al 2014;Shieh et al 2015;Liang et al 2015a;Lian et al 2016;Liao et al 2017). All the above methods majorly rely on solutionbased procedures.…”