Abstract:
:Progesterone 5β-reductases (P5βRs) are involved in 5β-cardenolide formation by stereo-specific reduction of the △4,5 double bond of steroid precursors. In this study a steroid 5β-reductase was identified in Capsella rubella (CrSt5βR1) and its function in steroid 5β-reduction was validated experimentally. CrSt5βR1 is capable of enantioselectively reducing the activated CC bond of broad substrates such as steroids and enones by using NADPH as a cofactor and therefore has the potential as a biocatalyst in organic synthesis. However, for industrial purposes the cheaper NADH is the preferred cofactor. By applying rational design based on literature and complementary mutagenesis strategies, we successfully identified two key amino acid residues determining the cofactor specificity of the enzyme. The R63 K mutation enables the enzyme to convert progesterone to 5β-pregnane-3,20-dione with NADH as cofactor, whereas the wild-type CrSt5βR1 is strictly NADPH-dependent. By further introducing the R64H mutation, the double mutant R63K_R64H of CrSt5βR1 was shown to increase enzymatic activity by13.8-fold with NADH as a cofactor and to increase the NADH/NADPH conversion ratio by 10.9-fold over the R63 K single mutant. This finding was successfully applied to change the cofactor specificity and to improve activity of other members of the same enzyme family, AtP5βR and DlP5βR. CrSt5βR1 mutants are expected to have the potential for biotechnological applications in combination with the well-established NADH regeneration systems.
journal_name
Enzyme Microb Technoljournal_title
Enzyme and microbial technologyauthors
Li Y,Pan H,Chang Y,Dong N,Zou L,Liang P,Tian W,Chang Zdoi
10.1016/j.enzmictec.2019.109483subject
Has Abstractpub_date
2020-03-01 00:00:00pages
109483eissn
0141-0229issn
1879-0909pii
S0141-0229(19)30221-2journal_volume
134pub_type
杂志文章abstract::Conductive materials with attached biofilms, were used as membrane filtration biocathodes to filter the effluent and supply electrons for denitrification. Stainless steel mesh and carbon felt were employed to fabricate membrane modules, and the two MFC systems were termed as M1 and M2, respectively. High effluent qual...
journal_title:Enzyme and microbial technology
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journal_title:Enzyme and microbial technology
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journal_title:Enzyme and microbial technology
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
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journal_title:Enzyme and microbial technology
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journal_title:Enzyme and microbial technology
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journal_title:Enzyme and microbial technology
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
doi:10.1016/j.enzmictec.2013.03.018
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
doi:10.1016/j.enzmictec.2016.11.001
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
doi:10.1016/j.enzmictec.2016.07.003
更新日期:2016-10-01 00:00:00
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
doi:10.1016/0141-0229(90)90056-v
更新日期:1990-06-01 00:00:00
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
doi:10.1016/s0141-0229(00)00272-6
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
doi:10.1016/s0141-0229(00)00277-5
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
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更新日期:2000-06-01 00:00:00
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journal_title:Enzyme and microbial technology
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doi:10.1016/j.enzmictec.2019.109393
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journal_title:Enzyme and microbial technology
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abstract::The full utilization of hemicellulose sugars (pentose and exose) present in lignocellulosic material, is required for an efficient bio-based fuels and chemicals production. Two recombinant thermophilic enzymes, an endo-1,4-β-mannanase from Dictyoglomus turgidum (DturCelB) and an α-galactosidase from Thermus thermophil...
journal_title:Enzyme and microbial technology
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journal_title:Enzyme and microbial technology
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
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journal_title:Enzyme and microbial technology
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journal_title:Enzyme and microbial technology
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
doi:10.1016/j.enzmictec.2017.10.010
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
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abstract::Even though many enzyme processes occur at the interface of an insoluble substrate, these reactions are generally much less studied than homogenous enzyme reactions in the aqueous bulk. Interfacial (or heterogeneous) enzyme reactions involve several reaction steps, and the established experimental approach to elucidat...
journal_title:Enzyme and microbial technology
pub_type: 杂志文章
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journal_title:Enzyme and microbial technology
pub_type: 杂志文章
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abstract::In the present investigation, the bacterium Escherichia coli (VM1) was isolated from a marine sediments of Ennore coastal water along southeast coast of India was exploited for its capability of Ag NPs synthesis. The derived nanoparticles were characterized employing ultraviolet-visible (UV-vis) spectroscopy, Fourier ...
journal_title:Enzyme and microbial technology
pub_type: 杂志文章
doi:10.1016/j.enzmictec.2016.09.008
更新日期:2016-12-01 00:00:00