The electrochemical reduction of oxygen is pivotal for advancing emerging energy technologies. Precise control over morphology and electronic structure is essential for enhancing catalytic activity and stability in the oxygen reduction reaction (ORR). In this study, a freestanding carbon electrode is developed by in-situ growth of carbon nanotube (CNT)-encapsulated bimetallic CoM (M = Ni, Fe, Mn, Cu) nanoparticles (NPs) within a hierarchical carbonized wood matrix (CoM@NWCC).
View Article and Find Full Text PDFThe photocatalytic conversion of plastic waste into value-added products using solar energy presents a promising approach for promoting environmental sustainability. Nonetheless, the emission of CO during the conventional photocatalytic degradation process remains a major hurdle that impedes its further development. In this study, we propose an efficient photocatalytic conversion of polyethylene plastic into syngas (CO+H mixtures) by using a ZnS/GaO Z-scheme heterojunction photocatalyst.
View Article and Find Full Text PDFA facile and efficient protocol for P(O)-O bond formation was discovered through NaIO/air-initiated phosphorylation of alcohols with H-phosphine oxides in water. This reaction showed good functional group tolerance and a broad substrate scope, providing an alternative method for constructing P(O)-O bonds. Mechanistic studies suggested that a phosphoryl radical-involving process from H-phosphine oxides facilitated the phosphorylation of alcohols under air.
View Article and Find Full Text PDFRuthenium (Ru) nanoparticles dispersed on carbon support are promising electrocatalysts for hydrogen evolution reaction (HER) due to strong electronic metal-carbon interactions (EMCIs). Defects engineering in carbon supports is an effective strategy to adjust EMCIs. We prepared nitrogen/sulfur co-doped carbon supported Ru nanoparticles (Ru@N/S-LC) using sodium lignosulfonate and urea as feedstocks.
View Article and Find Full Text PDFCytochrome P450 enzymes are promising biocatalysts for industrial use because they catalyze site-selective C-H oxidation and have diverse catalytic reactions and a broad substrate range. In this study, the 2α-hydroxylation activity of CYP154C2 from Streptomyces avermitilis MA-4680T toward androstenedione (ASD) was identified by an conversion assay. The testosterone (TES)-bound structure of CYP154C2 was solved at 1.
View Article and Find Full Text PDFDue to the complexity of the synthetic process of cobalt phosphides (CoP), ongoing efforts concentrate on simplifying the preparation process of CoP. In this work, amino tris(methylene phosphonic acid) (ATMP, L1) and melamine (MA, L2) are assembled into two-dimensional (2D) organic nanostructures by hydrogen bonding and ionic interactions a supramolecular assembly, which greatly weakens the coordination ability of L1 with Co. As the introduced L2 is rich in carbon and nitrogen, it allows the cobalt-organophosphate complex to be placed under a strongly reducing atmosphere during the high-temperature calcination process to achieve an phosphating purpose.
View Article and Find Full Text PDFCytochrome P450 enzymes (CYPs or P450s) are ubiquitous heme-dependent enzymes that catalyze the monooxygenation of non-activated C-H bonds to modify the structure of the substrate. In this study, we heterologously expressed CYP107X1 from Streptomyces avermitilis and conducted in vitro substrate screening using the alternative redox partners putidaredoxin and putidaredoxin reductase. CYP107X1 catalyzed the 16α-hydroxylation of progesterone with regio- and stereoselectivity.
View Article and Find Full Text PDFReasonable control of the redox states within the catalytic units together with the interconnection degrees of the substrate is of great significance in the modulation of a well-performing transducer. Herein, a novel carbon black (CB)-modified copper metal-organic framework nanomaterial (CB@Cu-MOF) prepared at room temperature was utilized as a precursor to synthesize mixed-valent copper-oxide composite catalysts (NC/CuO-). By tuning the carbonization process of the precursor at different temperatures ( = 100 °C, 200 °C, 300 °C and 400 °C), the different ratio configurations of the redox-alternated CuO portions were successfully controlled with the simultaneous effective tailoring of the defect abundance in the N-doped carbon substrate.
View Article and Find Full Text PDFCytochrome P450 enzymes (P450s) are versatile biocatalysts, which insert a molecular oxygen into inactivated C-H bonds under mild conditions. CYP105D7 from Streptomyces avermitilis has been reported as a bacterial substrate-promiscuous P450 which catalyzes the hydroxylation of 1-deoxypentalenic acid, diclofenac, naringenin, compactin and steroids. In this study, CYP105D7 catalyzes hydroxylation, epoxidation and dehydrogenation of capsaicin, a pharmaceutical agent, revealing its functional diversity.
View Article and Find Full Text PDFSince 1970s, aplysiatoxins (ATXs), a class of biologically active dermatoxins, were identified from the marine mollusk , whilst further research indicated that ATXs were originally metabolized by cyanobacteria. So far, there have been 45 aplysiatoxin derivatives discovered from marine cyanobacteria with various geographies. Recently, we isolated two neo-debromoaplysiatoxins, neo-debromoaplysiatoxin G () and neo-debromoaplysiatoxin H () from the cyanobacterium sp.
View Article and Find Full Text PDFCytochrome P450 enzymes (P450 or CYP) are some of the most versatile biocatalysts, and offer advantages for oxidizing unreactive C-H bonds in mild conditions. In this study, we identified a novel cytochrome P450 154C2 from Streptomyces avermitilis and characterized its function in 2α-hydroxylation of testosterone with regio- and stereoselectivity. To investigate the efficiency of electron transfer, we conducted biotransformation using two different P450 redox partners-RhFRED (RhF reductase domain) from Rhodococcus sp.
View Article and Find Full Text PDFOur previous study showed that CYP105D7, a substrate-promiscuous P450, catalyzes the hydroxylation of 1-deoxypentalenic acid, diclofenac, naringenin, and compactin. In this study, 14 steroid compounds were screened using recombinant cells harboring genes encoding CYP105D7 and redox partners (Pdx/Pdr, RhFRED, and FdxH/FprD), and the screening identified steroid A-ring 2β- and D-ring 16β-hydroxylation activity. Wild-type CYP105D7 was able to catalyze the hydroxylation of five steroids (testosterone, progesterone, 4-androstene-3,17-dione, adrenosterone, and cortisone) with low (<10%) conversion rates.
View Article and Find Full Text PDFBacterial secondary metabolites have huge application potential in multiple industries. Biosynthesis of bacterial secondary metabolites are commonly encoded in a set of genes that are organized in the secondary metabolism biosynthetic gene clusters (SMBGCs). The development of genome sequencing technology facilitates mining bacterial SMBGCs.
View Article and Find Full Text PDFReliable and sensitive detection of xanthine has important medical and biological significance. In this work, a novel three-dimensional (3D) conductive polymer hydrogel of polyaniline (PAni) was feasibly prepared using aniline (Ani), amino trimethylene phosphonic acid (ATMP) and ammonium persulfate ((NH)SO) as monomer, gelatinizing agent and oxidizing agent, respectively. Protonation of aniline can be achieved by ATMP, inducing good conductivity of the obtained hydrogel.
View Article and Find Full Text PDFSynth Syst Biotechnol
December 2018
The cytochrome P450 enzymes are ubiquitous heme-thiolate proteins performing regioselective and stereoselective oxygenation reactions in cellular metabolism. Due to their broad substrate scope and catalytic versatility, P450 enzymes are also attractive candidates for many industrial and biopharmaceutical applications. For particular uses, enzyme properties of P450s can be further optimized through directed evolution, rational, and semi-rational engineering approaches, all of which introduce mutations within the P450 structures.
View Article and Find Full Text PDFTo further increase the energy and power densities of lithium-ion batteries (LIBs), monoclinic Li V (PO ) attracts much attention. However, the intrinsic low electrical conductivity (2.4 × 10 S cm ) and sluggish kinetics become major drawbacks that keep Li V (PO ) away from meeting its full potential in high rate performance.
View Article and Find Full Text PDFCompactin and pravastatin are competitive cholesterol biosynthesis inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase and belong to the statin drugs; however, the latter shows superior pharmacokinetic characteristics. Previously, we reported that the bacterial P450, CYP105D7, from can catalyze the hydroxylation of 1-deoxypentalenic acid, diclofenac, and naringenin. Here, we demonstrate that CYP105D7 could also catalyze compactin hydroxylation in vitro.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
April 2015
Diclofenac is a nonsteroidal anti-inflammatory drug. It undergoes hydroxylation by mammalian cytochrome P450 enzymes at 4'- and/or 5'-positions. A bacterial P450 enzyme, CYP105D7 from Streptomyces avermitilis, has been shown to catalyze hydroxylation of 1-deoxypentalenic acid and an isoflavone daidzein.
View Article and Find Full Text PDFPentalenic acid (1) has been isolated from many Streptomyces sp. as a co-metabolite of the sesquiterpenoid antibiotic pentalenolactone and related natural products. We have previously reported the identification of a 13.
View Article and Find Full Text PDFThe polyene macrolide antibiotic filipin is widely used as a probe for cholesterol and a diagnostic tool for type C Niemann-Pick disease. Two position-specific P450 enzymes are involved in the post-polyketide modification of filipin during its biosynthesis, thereby providing molecular diversity to the "filipin complex." CYP105P1 and CYP105D6 from Streptomyces avermitilis, despite their high sequence similarities, catalyze filipin hydroxylation at different positions, C26 and C1', respectively.
View Article and Find Full Text PDFThe polyene macrolide antibiotic filipin is widely used as a probe for cholesterol in biological membranes. The filipin biosynthetic pathway of Streptomyces avermitilis contains two position-specific hydroxylases, C26-specific CYP105P1 and C1'-specific CYP105D6. In this study, we describe the three X-ray crystal structures of CYP105P1: the ligand-free wild-type (WT-free), 4-phenylimidazole-bound wild-type (WT-4PI), and ligand-free H72A mutant (H72A-free) forms.
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