Diverse N-Oxidation of Primary Aromatic Amines Controlled by Engineered P450 Peroxizyme Variants Facilitated by Dual-Functional Small Molecule.

Amine oxidation is an important organic reaction for the production of high-value N-containing compounds. However, it is still challenging to control the reactivity of active N-centered radicals to selectively access N-oxidation products. Herein, this study reports the engineering of cytochrome P450BM3 into multifunctional N-oxidizing enzymes with the assistance of dual-functional small molecules (DFSM) to selectively produce N-oxygenation (i.

Unique Fn3-like biosensor in σ/anti-σ factors for regulatory expression of major cellulosomal scaffoldins in Pseudobacteroides cellulosolvens.

Lignocellulolytic clostridia employ multiple pairs of alternative σ/anti-σ (SigI/RsgI) factors to regulate cellulosomal components for substrate-specific degradation of cellulosic biomass. The current model has proposed that RsgIs use a sensor domain to bind specific extracellular lignocellulosic components and activate cognate SigIs to initiate expression of corresponding cellulosomal enzyme genes, while expression of scaffoldins can be initiated by several different SigIs. Pseudobacteroides cellulosolvens contains the most complex known cellulosome system and the highest number of SigI-RsgI regulons yet discovered.

Structural basis for substrate flexibility of the O-methyltransferase MpaG' involved in mycophenolic acid biosynthesis.

MpaG' is an S-adenosyl-L-methionine (SAM)-dependent methyltransferase involved in the compartmentalized biosynthesis of mycophenolic acid (MPA), a first-line immunosuppressive drug for organ transplantations and autoimmune diseases. MpaG' catalyzes the 5-O-methylation of three precursors in MPA biosynthesis including demethylmycophenolic acid (DMMPA), 4-farnesyl-3,5-dihydroxy-6-methylphthalide (FDHMP), and an intermediate containing three fewer carbon atoms compared to FDHMP (FDHMP-3C) with different catalytic efficiencies. Here, we report the crystal structures of S-adenosyl-L-homocysteine (SAH)/DMMPA-bound MpaG', SAH/FDHMP-3C-bound MpaG', and SAH/FDHMP-bound MpaG' to understand the catalytic mechanism of MpaG' and structural basis for its substrate flexibility.

Structural investigation of Fun168A unraveling the recognition mechanism of endo-1,3-fucanase towards sulfated fucan.

Background: Sulfated fucan has gained interest due to its various physiological activities. Endo-1,3-fucanases are valuable tools for investigating the structure and establishing structure-activity relationships of sulfated fucan. However, the substrate recognition mechanism of endo-1,3-fucanases towards sulfated fucan remains unclear, limiting the application of endo-1,3-fucanases in sulfated fucan research.

Composition of Lignocellulose Hydrolysate in Different Biorefinery Strategies: Nutrients and Inhibitors.

The hydrolysis and biotransformation of lignocellulose, i.e., biorefinery, can provide human beings with biofuels, bio-based chemicals, and materials, and is an important technology to solve the fossil energy crisis and promote global sustainable development.

A cellulosomal double-dockerin module from Clostridium thermocellum shows distinct structural and cohesin-binding features.

Cellulosomes are intricate cellulose-degrading multi-enzymatic complexes produced by anaerobic bacteria, which are valuable for bioenergy development and biotechnology. Cellulosome assembly relies on the selective interaction between cohesin modules in structural scaffolding proteins (scaffoldins) and dockerin modules in enzymes. Although the number of tandem cohesins in the scaffoldins is believed to determine the complexity of the cellulosomes, tandem dockerins also exist, albeit very rare, in some cellulosomal components whose assembly and functional roles are currently unclear.

Deciphering the stereo-specific catalytic mechanisms of cis-epoxysuccinate hydrolases producing L(+)-tartaric acid.

Microbial epoxide hydrolases, cis-epoxysuccinate hydrolases (CESHs), have been utilized for commercial production of enantiomerically pure L(+)- and D(-)-tartaric acids for decades. However, the stereo-catalytic mechanism of CESH producing L(+)-tartaric acid (CESH[L]) remains unclear. Herein, the crystal structures of two CESH[L]s in ligand-free, product-complexed, and catalytic intermediate forms were determined.

Structure of the transcription open complex of distinct σ factors.

Bacterial σ factors of the σ-family are widespread in Bacilli and Clostridia and are involved in the heat shock response, iron metabolism, virulence, and carbohydrate sensing. A multiplicity of σ paralogues in some cellulolytic bacteria have been shown to be responsible for the regulation of the cellulosome, a multienzyme complex that mediates efficient cellulose degradation. Here, we report two structures at 3.

Structural insight into why S-linked glycosylation cannot adequately mimic the role of natural O-glycosylation.

There is an increasing interest in using S-glycosylation as a replacement for the more commonly occurring O-glycosylation, aiming to enhance the resistance of glycans against chemical hydrolysis and enzymatic degradation. However, previous studies have demonstrated that these two types of glycosylation exert distinct effects on protein properties and functions. In order to elucidate the structural basis behind the observed differences, we conducted a systematic and comparative analysis of 6 differently glycosylated forms of a model glycoprotein, CBM, using NMR spectroscopy and molecular dynamic simulations.

Artificial Small Molecules as Cofactors and Biomacromolecular Building Blocks in Synthetic Biology: Design, Synthesis, Applications, and Challenges.

Enzymes are essential catalysts for various chemical reactions in biological systems and often rely on metal ions or cofactors to stabilize their structure or perform functions. Improving enzyme performance has always been an important direction of protein engineering. In recent years, various artificial small molecules have been successfully used in enzyme engineering.

Key roles of β-glucosidase BglA for the catabolism of both laminaribiose and cellobiose in the lignocellulolytic bacterium Clostridium thermocellum.

The thermophilic bacterium Clostridium thermocellum efficiently degrades polysaccharides into oligosaccharides. The metabolism of β-1,4-linked cello-oligosaccharides is initiated by three enzymes, i.e.

The characteristic structure of funoran could be hydrolyzed by a GH86 family enzyme (Aga86A_Wa): Discovery of the funoran hydrolase.

Funoran, agarose and porphyran all belong to agaran, and share the similar skeleton. Although the glycoside hydrolase for agarose and porphyran, i.e.

Essential autoproteolysis of bacterial anti-σ factor RsgI for transmembrane signal transduction.

Autoproteolysis has been discovered to play key roles in various biological processes, but functional autoproteolysis has been rarely reported for transmembrane signaling in prokaryotes. In this study, an autoproteolytic effect was discovered in the conserved periplasmic domain of anti-σ factor RsgIs from , which was found to transmit extracellular polysaccharide-sensing signals into cells for regulation of the cellulosome system, a polysaccharide-degrading multienzyme complex. Crystal and NMR structures of periplasmic domains from three RsgIs demonstrated that they are different from all known proteins that undergo autoproteolysis.

Integrated lactic acid production from lignocellulosic agricultural wastes under thermal conditions.

The production of lactic acid (LA) from agricultural wastes attracts great attention because of the sustainability and abundance of lignocellulosic feedstocks, as well as the increasing demand for biodegradable polylactic acid. In this study, we isolated a thermophilic strain Geobacillus stearothermophilus 2H-3 for use in robust production of L-(+)LA under the optimal conditions of 60 °C, pH 6.5, which were consistent with the whole-cell-based consolidated bio-saccharification (CBS) process.

Molecular Basis of TcdR-Dependent Promoter Activity for Toxin Production by Studied by a Heterologous Reporter System.

The alternative σ factor TcdR controls the synthesis of two major enterotoxins: TcdA and TcdB in . Four potential TcdR-dependent promoters in the pathogenicity locus of showed different activities. In this study, we constructed a heterologous system in to investigate the molecular basis of TcdR-dependent promoter activity.

Hydrogenase and Nitrogenase: Key Catalysts in Biohydrogen Production.

Hydrogen with high energy content is considered to be a promising alternative clean energy source. Biohydrogen production through microbes provides a renewable and immense hydrogen supply by utilizing raw materials such as inexhaustible natural sunlight, water, and even organic waste, which is supposed to solve the two problems of "energy supply and environment protection" at the same time. Hydrogenases and nitrogenases are two classes of key enzymes involved in biohydrogen production and can be applied under different biological conditions.

Structural characterization on a β-agarase Aga86A_Wa from Wenyingzhuangia aestuarii reveals the prevalent methyl-galactose accommodation capacity of GH86 enzymes at subsite -1.

Agarans are sulfated galactans extracted from red algae with high structural complexity, of which natural methylation often occurs on the O-6 position of its β-d-galactopyranose units. Although many agaran degrading enzymes, including agarases and porphyranases, have been characterized, little attention has been paid to the tolerance of methyl groups at cleavage subsites. In this study, the structure of GH86 β-agarase Aga86A_Wa from Wenyingzhuangia aestuarii was determined by X-ray crystallography and investigated from a structural biology perspective.

Engineering Cytochrome P450BM3 Enzymes for Direct Nitration of Unsaturated Hydrocarbons.

Applications of the peroxidase activity of cytochrome P450 enzymes in synthetic chemistry remain largely unexplored. We present herein a protein engineering strategy to increase cytochrome P450BM3 peroxidase activity for the direct nitration of aromatic compounds and terminal aryl-substituted olefins in the presence of a dual-functional small molecule (DFSM). Site-directed mutations of key active-site residues allowed the efficient regulation of steric effects to limit substrate access and, thus, a significant decrease in monooxygenation activity and increase in peroxidase activity.

Regiodivergent and Enantioselective Hydroxylation of C-H bonds by Synergistic Use of Protein Engineering and Exogenous Dual-Functional Small Molecules.

It is a great challenge to optionally access diverse hydroxylation products from a given substrate bearing multiple reaction sites of sp and sp C-H bonds. Herein, we report the highly selective divergent hydroxylation of alkylbenzenes by an engineered P450 peroxygenase driven by a dual-functional small molecule (DFSM). Using combinations of various P450BM3 variants with DFSMs enabled access to more than half of all possible hydroxylated products from each substrate with excellent regioselectivity (up to >99 %), enantioselectivity (up to >99 % ee), and high total turnover numbers (up to 80963).

Discovery of a cysteine-rich peptide with glycation modification from Achyranthes bidentata Blume.

Cysteine-rich peptides (CRPs) are stable molecules that contain multiple disulphide bonds. Various CRPs are found in plants and animals, representing potential compounds for drug development with diverse activities. Modification of CRPs, such as glycation, has attracted increased attention due to its special structural and functional properties.

Diversification of phenolic glucosides by two UDP-glucosyltransferases featuring complementary regioselectivity.

Background: Glucoside natural products have been showing great medicinal values and potentials. However, the production of glucosides by plant extraction, chemical synthesis, and traditional biotransformation is insufficient to meet the fast-growing pharmaceutical demands. Microbial synthetic biology offers promising strategies for synthesis and diversification of plant glycosides.

Deciphering Cellodextrin and Glucose Uptake in .

Sugar uptake is of great significance in industrially relevant microorganisms. Clostridium thermocellum has extensive potential in lignocellulose biorefineries as an environmentally prominent, thermophilic, cellulolytic bacterium. The bacterium employs five putative ATP-binding cassette transporters which purportedly take up cellulose hydrolysates.

Development of highly efficient whole-cell catalysts of cis-epoxysuccinic acid hydrolase by surface display.

Bacterial cis-epoxysuccinic acid hydrolases (CESHs) are intracellular enzymes used in the industrial production of enantiomeric tartaric acids. The enzymes are mainly used as whole-cell catalysts because of the low stability of purified CESHs. However, the low cell permeability is the major drawback of the whole-cell catalyst.