Alteration of substrate specificities of thermophilic α/β hydrolases through domain swapping and domain interface optimization

Characteration of a novel arylesterase from probiotics Lacticaseibacillus rhamnosus GG with the preference for medium- and long-chain p-Nitrophenyl esters

We prospected a novel arylesterase LggEst from the probiotics Lacticaseibacillus rhamnosus GG by genome mining strategy, and characterized the enzymatic properties in detail. Biochemical characterization revealed that arylesterase LggEst presented high activity at a wide range of temperatures from 25 to 65 °C with maximum activity at 50 °C. LggEst maintained high activity in the pH range from 5.5 to 7.5 with optimum pH of 6.5. LggEst might efficiently hydrolyze a series of aryl substrates p-nitrophenyl esters with different acyl chain lengths. LggEst displayed the V_max from 2.8 to 77.3 μmol min^-1 mg^-1 protein and the k _cat from 1.8 to 48.8 s^-1 with the highest catalytic activity on pNPC6. The K _M of LggEst on different substrates varied significantly from 4.9 μM to 5.6 mM with the highest affinity on pNPC10. LggEst exhibited the preference for medium- and long-chain p-nitrophenyl esters. LggEst showed remarkable thermostability at 45 °C. LggEst could be tolerant of several organic solvents at the concentration of 10% and DMSO and methanol at the concentration of 20%. Catalytic activity of LggEst was improved by 12% in the presence of 20% ethylene glycol. LggEst was resistant to high concentrations of sodium citrate and sodium chloride. Notably, enzymatic activity of LggEst was significantly enhanced in the presence of 0.1% sodium deoxycholate at high temperatures.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-03053-7.

Inulin hydrolysis by inulinase immobilized covalently on magnetic nanoparticles prepared with wheat gluten hydrolysates

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Fe₃O₄@WGHs nanoparticles were synthesized as a novel carrier with narrow particle size.

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Inulin hydrolyzed by immobilized inulinase on Fe₃O₄@WGHs nanopeptides.

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Optimum temperature increased while, pH and K_m values decreased after immobilization.

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Enzyme half-life and reusability were dramatically increased after Immobilization.

Inulinase can produce a high amount of fructose syrup from inulin in a one-step enzymatic process. Inulinase from Aspergillus niger was immobilized covalently on Fe₃O₄ magnetic nanoparticles functionalized with wheat gluten hydrolysates (WGHs). Wheat gluten was enzymatically hydrolyzed by two endopeptidases Alcalase and Neutrase and related nanoparticles were prepared by desolvation method. Magnetite nanoparticles were coated with WGHs nanoparticles and then inulinase was immobilized onto it using glutaraldehyde as crosslinking agent. Parallel studies employing differential scanning calorimetry and field emmision scanning electron microscopy were carried out to observe functional and structural variations in free inulinase during immobilization. Optimum temperature of immobilized inulinase was increased, while, pH and K_m values were decreased compared to free enzyme. Overall, a 12.3 folds rise was detected in enzyme half-life value after Immobilization at 75 °C and enzyme preserved 70% of its initial activity after 12 cycles of hydrolysis with 75% of enzyme loading.

CODV-Ig, a universal bispecific tetravalent and multifunctional immunoglobulin format for medical applications

Bispecific immunoglobulins (Igs) typically contain at least two distinct variable domains (Fv) that bind to two different target proteins. They are conceived to facilitate clinical development of biotherapeutic agents for diseases where improved clinical outcome is obtained or expected by combination therapy compared to treatment by single agents. Almost all existing formats are linear in their concept and differ widely in drug-like and manufacture-related properties. To overcome their major limitations, we designed cross-over dual variable Ig-like proteins (CODV-Ig). Their design is akin to the design of circularly closed repeat architectures. Indeed, initial results showed that the traditional approach of utilizing (G4S)x linkers for biotherapeutics design does not identify functional CODV-Igs. Therefore, we applied an unprecedented molecular modeling strategy for linker design that consistently results in CODV-Igs with excellent biochemical and biophysical properties. CODV architecture results in a circular self-contained structure functioning as a self-supporting truss that maintains the parental antibody affinities for both antigens without positional effects. The format is universally suitable for therapeutic applications targeting both circulating and membrane-localized proteins. Due to the full functionality of the Fc domains, serum half-life extension as well as antibody- or complement-dependent cytotoxicity may support biological efficiency of CODV-Igs. We show that judicious choice in combination of epitopes and paratope orientations of bispecific biotherapeutics is anticipated to be critical for clinical outcome. Uniting the major advantages of alternative bispecific biotherapeutics, CODV-Igs are applicable in a wide range of disease areas for fast-track multi-parametric drug optimization.

Molecular dynamics simulations of acylpeptide hydrolase bound to chlorpyrifosmethyl oxon and dichlorvos

Acylpeptide hydrolases (APHs) catalyze the removal of N-acylated amino acids from blocked peptides. Like other prolyloligopeptidase (POP) family members, APHs are believed to be important targets for drug design. To date, the binding pose of organophosphorus (OP) compounds of APH, as well as the different OP compounds binding and inducing conformational changes in two domains, namely, α/β hydrolase and β-propeller, remain poorly understood. We report a computational study of APH bound to chlorpyrifosmethyl oxon and dichlorvos. In our docking study, Val471 and Gly368 are important residues for chlorpyrifosmethyl oxon and dichlorvos binding. Molecular dynamics simulations were also performed to explore the conformational changes between the chlorpyrifosmethyl oxon and dichlorvos bound to APH, which indicated that the structural feature of chlorpyrifosmethyl oxon binding in APH permitted partial opening of the β-propeller fold and allowed the chlorpyrifosmethyl oxon to easily enter the catalytic site. These results may facilitate the design of APH-targeting drugs with improved efficacy.

Purification and immobilization of the recombinant Brassica oleracea Chlorophyllase 1 (BoCLH1) on DIAION®CR11 as potential biocatalyst for the production of chlorophyllide and phytol

Recombinant Brassica oleracea chlorophyllase 1 (BoCLH1) with a protein molecular weight of 38.63 kDa was successfully expressed in E. coli and could catalyze chlorophyll (Chl) hydrolysis to chlorophyllide and phytol in vitro. In this study, we used DIAION^®CR11, a highly porous cross-linked polystyrene divinylbenzene-based metal chelator, for purifying and immobilizing the poly (His)-tagged enzyme. The Cu(II) showed the highest protein adsorption (9.2 ± 0.43 mg/g gel) and enzyme activity (46.3 ± 3.14 U/g gel) for the immobilization of the poly (His)-tagged recombinant BoCLH1 compared with other metal chelators. Biochemical analysis of the immobilized enzyme showed higher chlorophyllase activity for Chl a hydrolysis in a weak base environment (pH 8.0), and activity above 70% was in a high-temperature environment, compared with the free enzyme. In addition, compared with free BoCLH1, the enzyme half-life (t_1/2) of the immobilized BoCLH1 increased from 25.42 to 54.35 min (approximately two-fold) at 60 °C. The immobilized enzyme retained a residual activity of approximately 60% after 17 cycles in a repeated-batch operation. Therefore, DIAION^®CR11Cu(II)-immobilized recombinant BoCLH1 can be repeatedly used to lower the cost and is potentially useful for the industrial production of chlorophyllide and phytol.