Cocrystal@protein-anchoring nanococktail for combinatorially treating multidrug-resistant cancer.

Multidrug resistance (MDR), the major mechanism by which various cancers develop specific resistance to therapeutic agents, has set up enormous obstacles to many forms of tumor chemotherapy. Traditional cocktail therapy administration, based on the combination of multiple drugs for anti-MDR chemotherapy, often suffers from inconsistent pharmacokinetic behaviors that cannot act synchronously on the lesions, leading to limited pharmacodynamic outcomes. Despite the emergence of nanomedicines, which has improved chemotherapeutic drugs' bioavailability and therapeutic effect on clinical application, these monotherapy-based nano-formulations still show poor progression in overcoming MDR.

Selective biosynthesis of a rhamnosyl nosiheptide by a novel bacterial rhamnosyltransferase.

Nosiheptide (NOS) is a thiopeptide antibiotic produced by the bacterium Streptomyces actuosus. The hydroxyl group of 3-hydroxypyridine in NOS has been identified as a promising site for modification, which we therefore aimed to rhamnosylate. After screening, Streptomyces sp.

A machine learning-based QSAR model reveals important molecular features for understanding the potential inhibition mechanism of ionic liquids to acetylcholinesterase.

The broad application of ionic liquids (ILs) has been hindered by uncertainties surrounding their ecotoxicity. In this work, a Quantitative Structure-Activity Relationship (QSAR) model was devised to predict the inhibition of ILs towards the activity of AChE, employing both Random Forest (RF) and eXtreme Gradient Boosting (XGBoost) machine learning approaches. Fourteen kings of essential molecular feature descriptors were screened from an initial roster of 244 descriptors through the application of a feature importance index and they showed a significant impact on the activity of AChE activity.

Cellular uptake and cytotoxicity of PEGylated MXene nanomaterials mediated by protein corona.

A stringent analysis of the biocompatibility of MXene is a necessary condition for assessing the biological risk of MXene. Owing to high surface free energy, MXene is capable of adsorbing a large amount of blood proteins to form MXene-protein corona complexes, however, a comprehensive understanding of the relationship between MXene and cellular physiological systems remains limited. Therefore, we investigated the cellular uptake and cytotoxicity effect of MXene TiCT and PEGylation TiCT mediated by human serum protein corona in THP-1 cells.

Design of a chimeric glycosyltransferase OleD for the site-specific O-monoglycosylation of 3-hydroxypyridine in nosiheptide.

To identify the potential role of the 3-hydroxyl group of the pyridine ring in nosiheptide (NOS) for its antibacterial activity against Gram-positive pathogens, enzymatic glycosylation was utilized to regio-selectively create a monoglycosyl NOS derivative, NOS-G. For this purpose, we selected OleD, a UDP glycosyltransferase from Streptomyces antibioticus that has a low productivity for NOS-G. Activity of the enzyme was increased by swapping domains derived from OleI, both single and in combination.

RNF20/RNF40 ameliorates streptozotocin-induced type 1 diabetes by activating vitamin D receptors .

Background: Type 1 diabetes is one of the chronic autoimmune diseases. Its features include the immune-triggered pancreatic beta-cells destruction. Ubiquitin ligases RNF20 and RNF40 have been discovered to participate into beta cells gene expression, insulin secretion, and expression of vitamin D receptors (VDRs).

A Type I/Type III PKS Hybrid Generates Cinnamomycin A-D.

3,5-Dihydroxybenzoic acid (3,5-DHBA), biosynthesized by type III PKS and tailoring enzymes, is an unconventional starter unit for bacterial type I PKS. Genome mining of 3,5-DHBA-specific biosynthetic gene clusters could lead to discovering new type I/type III PKS hybrids. Herein, we report the discovery and characterization of atypical compounds, namely cinnamomycin A-D, exhibiting selective antiproliferative activity.

Efficient snailase-based production of mogrol from Luo Han Guo extract in an aqueous-organic system.

To solve the insufficient availability of mogrol, an 11α-hydroxy aglycone of mogrosides in Siraitia grosvenorii, snailase was employed as the enzyme to completely deglycosylate LHG extract containing 50% mogroside V. Other commonly used glycosidases performed less efficiently. Response surface methodology was conducted to optimize the productivity of mogrol, which peaked at 74.

Influences of protein-corona on stability and aggregation kinetics of TiCT nanosheets in aquatic environment.

Proteins existed in aquatic environments strongly influence the transport, fate of nanomaterials due to the formation of protein-corona surrounding nanomaterials. To date, how do proteins affect the aggregation behaviors of MXene, a new family of two-dimensional materials, in aquatic environment remains unknown. Here the aggregation kinetics of MXene TiCT nanosheets in various electrolytes (NaCl, CaCl and NaSO) was investigated by time-resolved dynamic light scattering in absence or presence of bovine serum albumin (BSA).

Recombinant Reg3α Prevents Islet β-Cell Apoptosis and Promotes β-Cell Regeneration.

Progressive loss and dysfunction of islet β-cells has not yet been solved in the treatment of diabetes. Regenerating protein (Reg) has been identified as a trophic factor which is demonstrated to be associated with pancreatic tissue regeneration. We previously produced recombinant Reg3α protein (rReg3α) and proved that it protects against acute pancreatitis in mice.

Enzymatic hydrolyzation of mogrosides in Luo Han Guo extract by NKA-adsorbed snailase improves its sensory profile.

Extracts of Siraitia grosvenorii (Swingle), in Chinese known as Luo Han Guo (LHG), is authorized for use as a natural sweetener. LHG is rich in mogroside V that contains five glucoses, but also contains mogroside IIIE and analogues with fewer than three glucose units that cause an unpleasant aftertaste, limiting the use of the extract. Snailase was applied here to convert mogroside V in LHG extract in favor of siamenoside I formation, the sweetest mogroside with a taste similar to sucrose.

Investigation of interaction between MXene nanosheets and human plasma and protein corona composition.

The composition of protein corona affects the behavior and fate of nanoparticles in biological systems, which strongly relates to the intrinsic properties of nanoparticles and proteins. Here, three types of MXene TiCT nanosheets are prepared by different etching methods, and certain physicochemical characteristics of the nanosheets before and after exposure to human plasma (HP) are characterized. The TiCT nanosheets with protein coronas suffer more easily from aggregation than pristine TiCT.

Engineering of a UDP-Glycosyltransferase for the Efficient Whole-Cell Biosynthesis of Siamenoside I in .

The combination of the insufficient availability and the complex structure of siamenoside I (SI), the sweetest glucoside isolated from to date, limited its use as a natural sweetener. To solve this problem, an improved biocatalyst, UGT-M2, was semi-rationally created by engineering the uridine diphosphate glycosyltransferase UGT94-289-2 from for the monoglucosylation of mogroside IIIE (MG IIIE) to SI. Subsequently, an engineered cell was constructed, which combined UGT-M2 with a UDP-glucose regeneration system to circumvent the need for expensive UDP-glucose to produce SI.

Inhibiting Phase Transfer of Protein Nanoparticles by Surface Camouflage-A Versatile and Efficient Protein Encapsulation Strategy.

Engineering a system with a high mass fraction of active ingredients, especially water-soluble proteins, is still an ongoing challenge. In this work, we developed a versatile surface camouflage strategy that can engineer systems with an ultrahigh mass fraction of proteins. By formulating protein molecules into nanoparticles, the demand of molecular modification was transformed into a surface camouflage of protein nanoparticles.

Efficient whole-cell biosynthesis of l-gulose by coupling mannitol-1-dehydrogenase with NADH oxidase.

L-Gulose is a rare aldohexose to serve as a building block for anticancer drug bleomycin and nucleoside-based antivirals. However, preparative inaccessibility and high cost have hindered its pharmaceutical application. Despite a regio- and stereo-selective enzymatic synthesis of l-gulose from d-sorbitol using a variant of NAD-dependent mannitol-1-dehydrogenase from Apium graveolens (mMDH) was explored, low efficiency and productivity caused by NADH accumulation or insufficient amount of NAD limited the practical utility of this process.

Selective enzymatic α-1,6- monoglucosylation of mogroside IIIE for the bio-creation of α-siamenoside I, a potential high-intensity sweetener.

A new compound, α-siamenoside I (α-SI), with a glucose unit selectively bound to the 6-hydroxyl group of the 24-O-β-glucosyl moiety of mogroside IIIE by α-1,6-glucosidic bond, was bio-created by two screened cyclodextrin glycosyltransferases with a maximum yield of 59.3%. Compared to mogroside IIIE, α-SI showed a significantly increased sweetness intensity (508 times sweeter than 5% sucrose), which is superior to siamenoside I (SI), the sweetest triterpenoid saponin isolated from Siraitia grosvenorii to date.

Enzymatic Monoglucosylation of Rubusoside and the Structure-Sweetness/Taste Relationship of Monoglucosyl Derivatives.

Monoglucosylation of rubusoside not only could increase its structural diversity but may also improve its taste. To biosynthesize the monoglucosyl rubusosides, a series of glycosyltransferases and glycosynthases were screened to identify the enzymes capable of specifically glycosylating the hydroxyl groups of the 13-O-β-d-glucosyl and 19-COO-β-d-glucosyl moieties. After structural characterization, the effect of structure on sweetness and taste was established based on these rubusoside-derived analogues, including two first characterized compounds.

Efficient Biocatalytic Preparation of Rebaudioside KA: Highly Selective Glycosylation Coupled with UDPG Regeneration.

Rebaudioside KA is a diterpene natural sweetener isolated in a trace amount from the leaves of Stevia rebaudiana. Selective glycosylation of rubusoside, a natural product abundantly presented in various plants, is a feasible approach for the biosynthesis of rebaudioside KA. In this study, bacterial glycosyltransferase OleD was identified to selectively transfer glucose from UDPG to 2'-hydroxyl group with a β-1,2 linkage at 19-COO-β-D-glucosyl moiety of rubusoside for the biosynthesis of rebaudioside KA.

Riboflavin Is Directly Involved in N-Dealkylation Catalyzed by Bacterial Cytochrome P450 Monooxygenases.

Like a vast number of enzymes in nature, bacterial cytochrome P450 monooxygenases require an activated form of flavin as a cofactor for catalytic activity. Riboflavin is the precursor of FAD and FMN that serves as indispensable cofactor for flavoenzymes. In contrast to previous notions, herein we describe the identification of an electron-transfer process that is directly mediated by riboflavin for N-dealkylation by bacterial P450 monooxygenases.

Identification of a heparosan heptasaccharide as an effective anti-inflammatory agent by partial desulfation of low molecular weight heparin.

Low molecular weight heparin (LMWH) possesses a dual function of anticoagulation and anti-inflammation. While the structures and mechanisms on its anticoagulation have been widely studied, the structural features responsible for the anti-inflammatory activity of LMWH remain to be explored. In the present study, guided by an anti-inflammation assay, a non-anticoagulant species was generated from partial desulfation of LMWH to fully retain the anti-inflammatory activity, from which five fractions were further separated and three of them were characterized by enzymatic degradation, hydrophobic labeling, C18-based HPLC and LC-MS/MS analyses.

Quantitative Assessment of the Absolute Purity of Thiopeptcin Reference Standard by H-NMR.

Quantitative nuclear magnetic resonance (qNMR) has emerged as an easy, rapid and reproducible method for various pharmaceuticals. In the current study, a general qNMR approach for calibrating the purity of the thiopeptcin reference standard (also known as nocathiacin I) was developed using sulfadoxine as an internal standard. Experimental conditions, such as the relaxation delay time and number of scans, were systematically optimized, and the method was validated with different analytical parameters, including selectivity, stability, linearity, precision and robustness.

Photoswitchable Heparinase III for Enzymatic Preparation of Low Molecular Weight Heparin.

A photocontrollable biocatalyst was rationally designed by site-specifically linking a photoswitchable azobenzene derivative to the only cysteine residue in heparinase III mutant (K130C). Upon photoswitch, the enzymatic degradation of heparin could be artificially controlled to produce low molecular weight heparin with more uniform molecular weight and an increase in anticoagulant activity.

Identification of truncated form of NosP as a transcription factor to regulate the biosynthesis of nosiheptide.

Nosiheptide (NOS), a typical member of the thiopeptides, possesses strong activities against multidrug-resistant, gram-positive bacterial pathogens. Similar to other thiopeptides, the biosynthetic pathway of NOS belongs to a ribosomally synthesized and posttranslationally modified peptide system. Bioinformatics analysis of the NOS gene cluster suggests that gene encodes a homologous protein of the antibiotic regulatory protein (SARP) family.

Optimization of critical medium components for enhancing antibacterial thiopeptide nocathiacin I production with significantly improved quality.

Nocathiacin I, a glycosylated thiopeptide antibiotic, displays excellent antibacterial activities against multidrug resistant bacterial pathogens. Previously, a novel nocathiacin I formulation for intravenous administration has been successfully developed and its aqueous solubility is greatly enhanced for clinical application. The purpose of the present study was to increase the fermentation titer of nocathiacin I and reduce or eliminate analogous impurities by screening the medium ingredients using response surface methodology.

Expanding the Catalytic Promiscuity of Heparinase III from Pedobacter heparinus.

Glycosaminoglycans (GAG) lyases are useful biocatalysts for the preparation of oligosaccharides, but their substrate spectra are limited to the same family. Thus, the degradation activity across families of GAG lyases is advantageous and desirable for various applications. In this study, residue Lys130 at the substrate entrance of monomeric heparinase III from Pedobacter heparinus ATCC 13125 was replaced by cysteine, and the resulting mutant K130C showed novel catalytic activity in degrading hyaluronic acid without affecting its native activity toward heparin and heparan sulfate.