Simple Purification and Immobilization of His-Tagged Organophosphohydrolase from Cell Culture Supernatant by Metal Organic Frameworks for Degradation of Organophosphorus Pesticides

Abstract

Coordinating unsaturated metal sites (CUS) on the surface of metal–organic frameworks (MOFs) could be used to adsorb His-tagged proteins. The specific adsorption between CUS and His-tagged proteins could reduce preparation steps, shorten preparation time, and could also avoid the binding between the metal ion of metalloenzyme active center and the chelating agent to ensure the enzyme activity. In this study, MIL-88A was synthesized by hydrothermal method and used to purify and immobilize His-tagged organophosphohydrolase (OpdA) in one step for organophosphate bioremediation. Under optimized conditions, OpdA@MIL-88A had a maximal activity of 1554 U/gprotein, which was nearly 5 times higher than free OpdA. Compared with free OpdA, OpdA@MIL-88A exhibited improved organic solvent tolerance, SDS tolerance, thermal stability, and storage stability. OpdA@MIL-88A was used to degrade organophosphorus pesticides on grapes and cucumbers. After reuse 6 times, OpdA@MIL-88A retained more than 66% and 61% of the initial activity, respectively. Therefore, this proposed strategy provided a facile and effective method for degradation of organophosphorus pesticides.

Hydrolysis of Organophosphorus Agents Catalyzed by Cobalt Nanoparticles Supported on Three-Dimensional Nitrogen-Doped Graphene

“…The V max (4.42 μM min −1 ) of Co/3DNG-2 is comparable to that of the reported molecularly imprinted polymer catalysts 34−36 but lower than that of OPH@MIL-88A. 37 We also investigated the effects of the pH, the content of the catalyst, and the reaction temperature on the catalytic hydrolysis of MP using Co/3DNG-2 as a catalyst systematically. As shown in Figure S8, under the optimal condition, 300 μg (14.58 μg of Co) of the catalyst, 80 °C, and pH 11.3, the conversion of MP can reach the maximum of 97.5% after reaction for 60 min, which is dramatically higher than those with 3DNG, Co NPs, and the physical mixture of Co NPs and 3DNG as catalysts (Figure S9).…”

“…As shown in Figure c, the K m value of Co/3DNG-2 is 0.14 mM, which is lower than those of some of the catalysts reported so far for MP hydrolysis (Table ), suggesting it has a high affinity for MP. The V max (4.42 μM min –1 ) of Co/3DNG-2 is comparable to that of the reported molecularly imprinted polymer catalysts − but lower than that of OPH@MIL-88A …”

Carrier Variety Used in Immobilization of His6-OPH Extends Its Application Areas

“…is based that fast and highly effective immobilization, and then isolation and purification of the enzyme itself occurs. The emerging coordination bonds between metal atoms in the carrier and nitrogen atoms in the imidazole rings of the polyhistidine sequence in the protein molecule make it possible to anchor the enzyme on the carrier quite firmly [ 2 , 22 , 23 ] and use it for a long time, in such an immobilized form, for the destruction of OPCs ( Table 1 , [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]). Of particular interest are such immobilization variants for the stabilization and repeated use of the enzyme in the degradation of OPC-polluting water systems [ 22 , 23 ].…”

“…The interest in such carriers is additionally motivated by the possible detoxifying effects of self-MOFs in relation to toxins, including OPCs (pesticides and CWA) [ 52 , 53 , 54 ]. Since then, MOFs as supports look very attractive for the obtainment and use of immobilized forms of His 6 -OPH [ 24 , 25 , 26 , 27 , 28 , 29 ].…”

Removal of organophosphorus agents via atomically dispersed Co on nitrogen-doped graphene: catalytic degradation and adsorption

“…Organophosphorus agents (OPs), used widely as pesticides for a long time, 1,2 can threaten human health even in trace amounts. 3,4 Thus, to efficiently remove OPs from food and water, many protocols have been proposed, such as chemical and biological degradation, 5,6 or/and adsorption. [7][8][9][10] In comparison, the removal of OPs based on the combination of adsorption and catalytic degradation seems more efficient.…”