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1.
J Basic Microbiol ; : e2400469, 2024 Sep 29.
Article in English | MEDLINE | ID: mdl-39344177

ABSTRACT

Monacolin K is a valuable secondary metabolite produced after a period of fermentation by Monascus purpureus; however, our current understanding of the regulatory mechanisms of its synthesis remains incomplete. This study conducted functional analysis on the key transcription factor, comp54181_c0, that is involved in the synthesis of monacolin K in Monascus. Mutant strains with either knockout or overexpression of comp54181_c0 were constructed using CRISPR/Cas9. A comparison between the knockout and overexpression strains revealed changes in fungal morphology and growth, with a significant increase in the production of Monascus pigments and monacolin K when comp54181_c0 was absent. Real-time fluorescence quantitative PCR analysis revealed that comp54181_c0 significantly influenced the transcription of key genes related to monacolin K biosynthesis in Monascus. In conclusion, our study elucidates the crucial role of comp54181_c0 in Monascus, enriches our understanding of fungal secondary metabolite development and regulation, and provides a foundation for the development and regulation of Monascus and monacolin K production.

2.
Biotechnol Lett ; 45(3): 401-410, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36650342

ABSTRACT

OBJECTIVES: To develop a modified CRISPR/Cas9 system with the ß-glucuronidase (GusA) reporter and a dual sgRNA cassette for Nonomuraea gerenzanensis (N. gerenzanensis). RESULTS: With the aid of a visual GusA reporter, the complicated and tedious process of cloning and gene identification could be abandoned entirely in the genetic editing of N. gerenzanensis. Moreover, introducing a dual sgRNA cassette into the CRISPR/Cas9 system significantly improved gene deletion efficiency compared to the single sgRNA element. Furthermore, the length of the homologous flanking sequences set to the lowest value of 500 bp in this system could still reach the relatively higher conjugation transfer frequency. CONCLUSIONS: The enhanced CRISPR/Cas9 system could efficiently perform genetic manipulation on the rare actinomycete N. gerenzanensis.


Subject(s)
Actinobacteria , CRISPR-Cas Systems , Gene Knockout Techniques , Gene Editing , Actinobacteria/genetics
3.
World J Microbiol Biotechnol ; 39(2): 67, 2023 Jan 03.
Article in English | MEDLINE | ID: mdl-36593427

ABSTRACT

Glycopeptide antibiotics (GPAs) are a family of non-ribosomal peptide natural products with polypeptide skeleton characteristics, which are considered the last resort for treating severe infections caused by multidrug-resistant Gram-positive pathogens. Over the past few years, an increasing prevalence of Gram-positive resistant strain "superbugs" has emerged. Therefore, more efforts are needed to study and modify the GPAs to overcome the challenge of superbugs. In this mini-review, we provide an overview of the complex biosynthetic gene clusters (BGCs), the ingenious crosslinking and tailoring modifications, the new GPA derivatives, the discoveries of new natural GPAs, and the new applications of GPAs in antivirus and anti-Gram-negative bacteria. With the development and interdisciplinary integration of synthetic biology, next-generation sequencing (NGS), and artificial intelligence (AI), more GPAs with new chemical structures and action mechanisms will constantly be emerging.


Subject(s)
Anti-Bacterial Agents , Artificial Intelligence , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Glycopeptides/pharmacology , Glycopeptides/chemistry
4.
Biotechnol Lett ; 44(2): 259-269, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34826003

ABSTRACT

OBJECTIVE: To improve the production of A40926, a combined strategy of constructing the engineered strain and optimizing the medium was implemented. RESULTS: The engineered strain lcu1 with the genetic features of dbv23 deletion and dbv3-dbv20 coexpression increased by 30.6% in the production of A40926, compared to the original strain. In addition, a combined medium called M9 was designed to be further optimized by the central composite design method. The optimized M9 medium was verified to significantly improve the A40926 yield from 257 to 332 mg l-1. CONCLUSIONS: The engineered strain lcu1 could significantly promote A40926 production in the optimized M9 medium, which indicated that the polygenic genetic manipulation and the media optimization played an equally important role in increasing the A40926 yield.


Subject(s)
Anti-Bacterial Agents , Teicoplanin , Actinobacteria , Anti-Bacterial Agents/pharmacology , Glycopeptides/genetics , Teicoplanin/analogs & derivatives
5.
Arch Microbiol ; 203(3): 1021-1032, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33124672

ABSTRACT

As intracellular parasites, viruses depend heavily on host cell structures and their functions to complete their life cycle and produce new viral particles. Viruses utilize or modulate cellular translational machinery to achieve efficient replication; the role of ribosome biogenesis and protein synthesis in viral replication particularly highlights the importance of the ribosome quantity and/or quality in controlling viral protein synthesis. Recently reported studies have demonstrated that ribosome biogenesis factors (RBFs) and ribosomal proteins (RPs) act as multifaceted regulators in selective translation of viral transcripts. Here we summarize the recent literature on RBFs and RPs and their association with subcellular redistribution, post-translational modification, enzyme catalysis, and direct interaction with viral proteins. The advances described in this literature establish a rationale for targeting ribosome production and function in the design of the next generation of antiviral agents.


Subject(s)
Gene Expression Regulation, Viral , Protein Biosynthesis , Ribosomal Proteins , Viral Proteins/biosynthesis , Viruses/metabolism , Protein Processing, Post-Translational , Ribosomal Proteins/genetics , Ribosomal Proteins/metabolism , Ribosomes/metabolism , Virus Replication
6.
Curr Microbiol ; 77(6): 1016-1023, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32002624

ABSTRACT

The glycopeptide A40926 biosynthesized by Nonomuraea gerenzanensis is a precursor of the second generation glycopeptide antibiotic dalbavancin. The skeleton of this glycopeptide consists of seven amino acids and is biosynthesized by the NRPS gene module. L-valine, a branched amino acid, is also a significant precursor for A40926 production. This study details the use of pH-responsive alginate-chitosan microspheres loaded with L-valine prepared by internal emulsification gelation. The effects of process and formulation variables on microsphere size, loading capacity, and encapsulation efficiency were investigated. Then, effects on A40926 production by the pH-responsive microspheres were evaluated in a 10-L fermenter. Results demonstrated that use of the pH-responsive microspheres could improve A40926 yield from 465 to 602 mg L-1 in a 10-L scale fermenter.


Subject(s)
Alginates/chemistry , Anti-Bacterial Agents/biosynthesis , Chitosan/chemistry , Microspheres , Teicoplanin/analogs & derivatives , Valine/chemistry , Actinobacteria/metabolism , Delayed-Action Preparations , Fermentation , Hydrogen-Ion Concentration , Particle Size , Surface Properties , Teicoplanin/biosynthesis , Valine/metabolism
7.
Biotechnol Lett ; 42(9): 1699-1706, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32314149

ABSTRACT

OBJECTIVE: To develop an inducible CRISPR/Cas9-Recombinase A (RecA) system to manipulate genes in Nonomuraea gerenzanensis effectively. RESULTS: Compared with traditional homologous recombination, the inducible CRISPR/Cas9 system achieved 68.8% editing efficiency, whereas, with both the inducible Cas9 and the overexpressed RecA, the efficiency of the combined genome editing system reached 100%. The dbv23-deleted mutant obtained by the inducible CRISPR/Cas9-RecA system was confirmed to produce more A40926 with an approximate yield of 200 mg L-1 than that of around 150 mg L-1 produced by the wild-type strain. CONCLUSIONS: This inducible CRISPR/Cas9-RecA system was successfully constructed and can be utilized as an efficient genome editing tool for Actinomyces able to shorten editing time simultaneously.


Subject(s)
Actinobacteria/genetics , CRISPR-Cas Systems/genetics , Gene Editing/methods , Rec A Recombinases/genetics , Actinomyces/genetics , Bacterial Proteins/genetics , Escherichia coli/genetics , Mutation/genetics
8.
Bioorg Med Chem Lett ; 24(18): 4435-4438, 2014 Sep 15.
Article in English | MEDLINE | ID: mdl-25176187

ABSTRACT

Phytochemical investigation of the ethanol extract of the aerial parts of Artemisia rupestris resulted in the isolation of three new guaiane sesquiterpenes, (1R,7R,10S)-1-hydroxy-3-oxoguaia-4,11(13)-dien-12-oic acid (1), (1R,7R,10S)-10-hydroxy-3-oxoguaia-4,11(13)-dien-12-oic acid (2), pechueloic acid 12-O-ß-d-glucopyranoside (3), together with 12 known compounds (4-15). The structures of these new compounds were established on the basis of extensive spectroscopic analysis and electronic circular dichroism (ECD) calculation. All isolates were evaluated for their in vitro inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages cells, and the structure-activity relationships were also discussed.


Subject(s)
Artemisia/chemistry , Nitric Oxide/biosynthesis , Sesquiterpenes, Guaiane/pharmacology , Animals , Cell Line , Dose-Response Relationship, Drug , Lipopolysaccharides/antagonists & inhibitors , Lipopolysaccharides/pharmacology , Macrophages/drug effects , Macrophages/metabolism , Mice , Molecular Structure , Sesquiterpenes, Guaiane/chemistry , Sesquiterpenes, Guaiane/isolation & purification , Structure-Activity Relationship
9.
Nat Prod Res ; : 1-7, 2024 Jul 27.
Article in English | MEDLINE | ID: mdl-39066549

ABSTRACT

Xanthohumol (XTH, 1), a major prenylated chalcone in hops, has attracted considerable interests because of its pharmaceutical potency. To explore more related derivatives of XTH, its biotransformation was performed using the in vitro microbial model. Fungus Mucor sp. exhibited a robust biocatalytic feature to transform the substrate. Preparative fungi-mediated biotransformation led to the isolation of two new (2 and 5) and eight known (3, 4 and 6-11) metabolites. The two new metabolites were identified as (2″R)-dihydroxanthohumol B (2) and xanthohumol L 4'-O-ß-D-glucopyranoside (5) based on the combined spectroscopic analysis. According to the cytotoxic activities of all metabolites, compounds 7 and 9 showed relatively sensitive cytotoxic activity against A375 and A549 cancer cell lines, respectively. These findings not only provided a biological approach to achieve the derivatives of XTH but also gave an information for the lead optimisation of XTH for the development of potential anti-cancer agents.

10.
J Fungi (Basel) ; 10(8)2024 Aug 05.
Article in English | MEDLINE | ID: mdl-39194879

ABSTRACT

Monascus is a filamentous fungus with a long history of application in China, which can produce a variety of secondary metabolites, including Monascus red pigments, Monascus orange pigments, Monascus yellow pigments, and citrinin. There is widespread attention being paid to natural pigments because of their safety. Among the many natural pigments, orange pigment has a wide range of applications because of its unique color, but current production levels in the orange pigment industry are limited to a certain extent due to the insufficiently wide range of sources and low production. In this study, the ARTP mutation was used to obtain a strain with high-yield orange pigment and low citrinin. The strain RS7 was obtained through two-step mutagenesis, and all three pigments were improved to different degrees. The color value of orange pigment was elevated from the original 108 U/mL to 180 U/mL, an increase of 66.7% compared to the original strain, and the citrinin content was reduced by 69%. The result of microscopic morphology showed that RS7 has more wrinkles and is more convex than the R1 strain, but there was little change between the two strains. Therefore, the ARTP mutation influenced the growth and the biosynthesis of pigments in Monascus. In addition, the conditions of ultrasonic extraction of Monascus pigments were optimized using the response surface, and the separation of pigments was achieved with the method of thin-layer chromatography. Pigment stability results showed that the temperature had no significant effect on orange pigment, while tea polyphenol could improve its stability. This study generated a strain with high-yielding orange pigment and could lay a foundation for the future application of Monascus orange pigment in the food industry.

11.
J Agric Food Chem ; 72(17): 9567-9580, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38627202

ABSTRACT

Monascus is a filamentous fungus that has been used in the food and pharmaceutical industries. When used as an auxiliary fermenting agent in the manufacturing of cheese, Monascus cheese is obtained. Citrinin (CIT) is a well-known hepatorenal toxin produced by Monascus that can harm the kidneys structurally and functionally and is frequently found in foods. However, CIT contamination in Monascus cheese is exacerbated by the metabolic ability of Monascus to product CIT, which is not lost during fermentation, and by the threat of contamination by Penicillium spp. that may be introduced during production and processing. Considering the safety of consumption and subsequent industrial development, the CIT contamination of Monascus cheese products needs to be addressed. This review aimed to examine its occurrence in Monascus cheese, risk implications, traditional control strategies, and new research advances in prevention and control to guide the application of biotechnology in the control of CIT contamination, providing more possibilities for the application of Monascus in the cheese industry.


Subject(s)
Cheese , Citrinin , Food Contamination , Monascus , Monascus/metabolism , Monascus/chemistry , Cheese/microbiology , Cheese/analysis , Citrinin/analysis , Food Contamination/analysis , Food Contamination/prevention & control , Humans , Fermentation
12.
AMB Express ; 13(1): 133, 2023 Nov 25.
Article in English | MEDLINE | ID: mdl-38006456

ABSTRACT

Nonomuraea gerenzanensis (N. gerenzanensis) is known for its ability to biosynthesize A40926, the precursor of the glycopeptide antibiotic (GPA) Dalbavancin. However, challenges and uncertainties related to the genetic manipulation of the rare actinomycetes remain. In order to improve the conjugation transfer of N. gerenzanensis, the crucial factors affecting conjugal transfer were evaluated, including agar medium, mycelial state, donor-recipient ratio, magnesium ion concentration, and antibiotic coverage time firstly. Additionally, γ-butyrolactone (GBL) for quorum sensing (QS) and antibiotics targeting bacterial walls were applied to evaluate their effects on conjugation transfer. As a result, the optimal conditions of 5%TSB of liquid medium, 24 h of the period time, V0.1 of agar medium, 30 mM of magnesium ion, the ratio 10:1 of donor-to-recipient, and 27 h of the overlaying time of antibiotic were determined. Furthermore, the results showed that autoinducer GBL and GPA teicoplanin had a synergetic effect on the conjugation transfer of N. gerenzanensis at a working concentration of 60 µM and 0.5 µg mL-1, respectively. The highest conjugation efficiency could reach about 1.3 depending on the optimal process conditions and the interference of QS and antibiotics.

13.
Int J Biol Macromol ; 230: 123191, 2023 Mar 01.
Article in English | MEDLINE | ID: mdl-36632964

ABSTRACT

Viral mRNA of coronavirus translates in an eIF4E-dependent manner, and the phosphorylation of eIF4E can modulate this process, but the role of p-eIF4E in coronavirus infection is not yet entirely evident. p-eIF4E favors the translation of selected mRNAs, specifically the mRNAs that encode proteins associated with cell proliferation, inflammation, the extracellular matrix, and tumor formation and metastasis. In the present work, two rounds of TMT relative quantitative proteomics were used to screen 77 cellular factors that are upregulated upon infection by coronavirus PEDV and are potentially susceptible to a high level of p-eIF4E. PEDV infection increased the translation level of ribosomal protein lateral stalk subunit RPLp2 (but not subunit RPLp0/1) in a p-eIF4E-dependent manner. The bicistronic dual-reporter assay and polysome profile showed that RPLp2 is essential for translating the viral mRNA of PEDV. RNA binding protein and immunoprecipitation assay showed that RPLp2 interacted with PEDV 5'UTR via association with eIF4E. Moreover, the cap pull-down assay showed that the viral nucleocapsid protein is recruited in m7GTP-precipitated complexes with the assistance of RPLp2. The heterogeneous ribosomes, which are different in composition, regulate the selective translation of specific mRNAs. Our study proves that viral mRNA and protein utilize translation factors and heterogeneous ribosomes for preferential translation initiation. This previously uncharacterized process may be involved in the selective translation of coronavirus.


Subject(s)
Coronavirus Infections , Coronavirus , Humans , Eukaryotic Initiation Factor-4E/metabolism , Protein Biosynthesis , Coronavirus/genetics , Proteomics , RNA, Messenger/genetics , RNA, Messenger/metabolism
14.
iScience ; 25(4): 104136, 2022 Apr 15.
Article in English | MEDLINE | ID: mdl-35342878

ABSTRACT

The global pandemic of COVID-19 caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection confers great threat to public health. Human breast milk is a complex nutritional composition to nourish infants and protect them from different kinds of infectious diseases including COVID-19. Here, we identified that lactoferrin (LF), mucin1 (MUC1), and α-lactalbumin (α-LA) from human breast milk inhibit SARS-CoV-2 infection using a SARS-CoV-2 pseudovirus system and transcription and replication-competent SARS-CoV-2 virus-like-particles (trVLP). In addition, LF and MUC1 inhibited multiple steps including viral attachment, entry, and postentry replication, whereas α-LA inhibited viral attachment and entry. Importantly, LF, MUC1, and α-LA possess potent antiviral activities toward variants such as B.1.1.7 (alpha), B.1.351 (beta), P.1 (gamma), and B.1.617.1 (kappa). Taken together, our study provides evidence that human breast milk components (LF, MUC1, and α-LA) are promising antiviral and potential therapeutic candidates warranting further development for treating COVID-19.

15.
Antiviral Res ; 207: 105406, 2022 11.
Article in English | MEDLINE | ID: mdl-36084850

ABSTRACT

Members of the tripartite motif (TRIM) protein family strongly induced by interferons (IFNs) are parts of the innate immune system with antiviral activity. However, it is still unclear which TRIMs could play important roles in hepatitis B virus (HBV) inhibition. Here, we identified that TRIM56 expression responded in IFN-treated HepG2-NTCP cells and HBV-infected liver tissues, which was a potent IFN-inducible inhibitor of HBV replication. Mechanistically, TRIM56 suppressed HBV replication via its Ring and C-terminal domain. C-terminal domain was essential for TRIM56 translocating from cytoplasm to nucleus during HBV infection. Further analysis revealed that TRIM56's Ring domain targeted IκBα for ubiquitination. This modification induced phosphorylation of p65, which subsequently inhibited HBV core promoter activity, resulting in the inhibition of HBV replication. The p65 was found to be necessary for NF-κB signal pathway to inhibit HBV replication. We verified our findings using HepG2-NTCP and primary human hepatocytes. Our findings reveal that TRIM56 is a critical antiviral immune effector and exerts an anti-HBV activity via NF-κB signal pathway, which is essential for inhibiting transcription of HBV covalently closed circular DNA.


Subject(s)
Hepatitis B virus , Hepatitis B , Antiviral Agents/pharmacology , DNA, Circular , Humans , Interferons/pharmacology , NF-KappaB Inhibitor alpha/genetics , NF-KappaB Inhibitor alpha/metabolism , NF-kappa B/metabolism , Tripartite Motif Proteins/genetics , Ubiquitin-Protein Ligases/genetics , Virus Replication
16.
Chemosphere ; 278: 130438, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34126682

ABSTRACT

Arsenic is frequently found in poultry waste, most of which is transformed from feed additive organoarsenicals, resulting in arsenic pollution of soils and water around poultry farms. The North China Plain, an important area for livestock breeding of China, was chosen to investigate the pollution characteristics and assess the health risk of arsenic around chicken farms. Among the 138 chicken farms sampled, almost no roxarsone, a common organoarsenical, was detected in chicken feeds, manure, and surface soils, while the detectable rate of other arsenic species was high. Because of long-term enrichment, the concentrations of arsenic species in manure were generally higher than that in feed. As(III) was the main inorganic arsenic species in the manure, where is reducing environment. In surface soils beneath the accumulated manure, As(V) was the predominant arsenic species with 100% detectable rate. The detectable rate and average concentrations at 0 cm were generally higher than those at 25 cm depth, indicating that arsenic accumulated in the surface soils. In addition, a typical conceptual diagram of arsenic was developed to clarify the pollution process from feed to soil. Through health risk assessment of inorganic arsenic, the carcinogenic risk (CR) and non-carcinogenic risk (non-CR) were both negligible. The city of Jiaozuo had the highest CR and non-CR, which was 11 times higher than that of the city with the lowest risks. This study presents a clear picture and evaluation of arsenic pollution on chicken farms, inspiring future studies assessing arsenic pollution after the ban of organoarsenicals.


Subject(s)
Arsenic , Soil Pollutants , Animals , Arsenic/analysis , Chickens , China , Farms , Manure , Risk Assessment , Soil , Soil Pollutants/analysis
17.
Int J Biol Macromol ; 178: 424-433, 2021 May 01.
Article in English | MEDLINE | ID: mdl-33662415

ABSTRACT

Amyloid proteins were recognized as the crucial cause of many senile diseases. In this study, the inhibitory effects of Sennoside A (SA) and Sennoside C (SC) on amyloid fibrillation were evaluated by the combination of biophysical approaches and molecular docking tool using human lysozyme (HL) as amyloid-forming model. The results of thioflavin-T (ThT), 8-anilino-1-naphthalenesulfonic acid (ANS) and congo red (CR) assays indicated that both SA and SC could inhibit the amyloid fibrillation of HL in a dose-dependent manner. The IC50 value of SA and SC on HL fibrillation was 200.09 µM and 186.20 µM, respectively. These findings were further verified by transmission electron microscopy (TEM) and atomic force microscopy (AFM), which showed that the addition of SA or SC could sharply reduce the amyloid fibrillation of HL. Additionally, the interactions of HL with SA and SC were investigated by steady-state fluorescence spectra and molecular docking studies. The results suggested that both SA and SC could bind to the binding pocket of HL and form a stable complex mainly via hydrogen bonds, van-der-Waals forces and hydrophobic interactions. In conclusion, our experiments revealed that both SA and SC can significantly inhibit amyloid fibrillation of HL.


Subject(s)
Amyloid/chemistry , Muramidase/chemistry , Protein Aggregates , Senna Extract/chemistry , Sennosides/chemistry , Humans
18.
J Biotechnol ; 324: 28-33, 2020 Dec 20.
Article in English | MEDLINE | ID: mdl-32971181

ABSTRACT

The semi-synthetic antibiotic dalbavancin is clinically used in the treatment of severe infections caused by multidrug resistant Gram-positive pathogens. So far, fermentation has still been the only approach for the production of A40926 in the industrial scale, which is used as the precursor of dalbavancin and biosynthesized by the rare actinomycete Nonomuraea gerenzanensis (N. gerenzanensis). Therefore, it is particularly essential and necessary to enhance the yield of A40926 continually. In this paper, we firstly assessed the activity of 6 heterologous promoters using the enhanced green fluorescence protein (EGFP) reporter system in N. gerenzanensis. Furthermore, the strongest constitutive promoter gapdh confirmed in this study was applied to separately overexpress the total of ten dbv genes involved in the A40926 biosynthesis. PCR and RT-qPCR were successively carried out to verify the mutant and the overexpression of dbv genes. As a consequence, the overexpression of dbv3 and dbv20 genes both increased the A40926 production remarkably. Based on the above consequences, a mutant strain named N320 laboring the co-expression of dbv3 and dbv20 was constructed. The results of fermentation showed that the N320 strain enhanced the yield of A40926 from 163 mg/L to 272 mg/L.


Subject(s)
Actinobacteria , Actinomycetales , Actinomycetales/genetics , Anti-Bacterial Agents , Teicoplanin/analogs & derivatives
19.
Int J Biol Macromol ; 161: 1393-1404, 2020 Oct 15.
Article in English | MEDLINE | ID: mdl-32750483

ABSTRACT

The misfolding of soluble protein to amyloid fibers or oligomers leads to cell membrane rupture, cell death, and a variety of amyloid-related diseases. Hence, inhibition of protein fibrillation is an important and promising method to prevent and treat these diseases. In this study, we have investigated the inhibitory effect of entacapone (Ent) on human lysozyme (HL) amyloid fibrillation using a combination of biophysical techniques; Rayleigh scattering (RLS) data indicated that Ent can reduce the aggregation of HL amyloid fibrillation with the inhibition constant (Λ) of (3.0 ± 0.5) × 103 M-1. This finding was further confirmed by thioflavin-T (ThT), 8-Anilino-1-naphthalenesulfonic acid (ANS) fluorescence assays and congo red (CR) binding absorption assays with an IC50 value of 125.89 ± 1.25 µM. Meanwhile, dynamic light scattering (DLS) showed that the size of HL amyloids decreases sharply after Ent treatment. This effect was positively correlated with Ent concentration. Atomic force microscopy (AFM) techniques confirmed that the formation of the fibril decreased significantly when HL was co-incubated with Ent. In addition, steady-state fluorescence spectra and synchronous fluorescence analysis suggested that the formation of stable complexes between Ent and HL contributes to maintain the alpha-helical structure of HL. The molecular docking study revealed that the Ent binds at the active pocket of HL with Glu35, Asp53, Gln58, Trp 64, Ala108 and Trp109 residues via hydrogen bonds, van-der-Waals forces and hydrophobic interactions. The epitope mapping of HL for its interaction with Ent was further elucidated using two-dimensional solution-state nuclear magnetic resonance (NMR) experiments. NMR results showed that the Trp64 and Trp109 of HL plays an important role for binding to Ent, correlating well with our docking result. Thus our study showed the potential of Ent to serve as an effective therapeutic agent for the therapy of amyloid-related diseases.


Subject(s)
Amyloid/chemistry , Catechols/chemistry , Catechols/pharmacology , Muramidase/chemistry , Nitriles/chemistry , Nitriles/pharmacology , Amyloid/drug effects , Humans , Hydrogen-Ion Concentration , Hydrophobic and Hydrophilic Interactions , Models, Chemical , Models, Molecular , Molecular Conformation , Protein Aggregates/drug effects , Protein Aggregation, Pathological/drug therapy , Spectrum Analysis , Structure-Activity Relationship
20.
J Org Chem ; 74(8): 3225-8, 2009 Apr 17.
Article in English | MEDLINE | ID: mdl-19296584

ABSTRACT

An array of carbazoles (23 examples) can be synthesized from substituted biaryl azides at 60 degrees C using substoichiometric quantities of Rh(2)(O(2)CC(3)F(7))(4) or Rh(2)(O(2)CC(7)H(15))(4).


Subject(s)
Azides/chemistry , Biphenyl Compounds/chemistry , Carbazoles/chemical synthesis , Rhodium/chemistry , Catalysis , Cyclization , Magnetic Resonance Spectroscopy , Molecular Structure , Stereoisomerism , Structure-Activity Relationship
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