scholarly journals Structural and Data Science-Driven Analysis to Assess Substrate Specificity of Diketopiperazine Reverse Prenyltransferase NotF: Cascade Biocatalytic Synthesis of (–)-Eurotiumin A

2021 ◽  
Author(s):  
Samantha P. Kelly ◽  
Vikram V. Shende ◽  
Autumn R. Flynn ◽  
Qingyun Dan ◽  
Ying Ye ◽  
...  
Keyword(s):  
Data Science ◽  
Early Stage ◽  
Oxidative Cyclization ◽  
Biologically Active ◽  
Full Potential ◽  
One Pot ◽  
Unique Approach ◽  
Substrate Promiscuity ◽  
Insight Into

Prenyltransfer is an early-stage carbon–hydrogen bond (C–H) functionalization prevalent in the biosynthesis of a diverse array of biologically active bacterial, fungal, plant, and metazoan diketopiperazine (DKP) alkaloids. Towards the development of a unified strategy for biocatalytic construction of prenylated DKP indole alkaloids, we sought to identify and characterize a substrate-permissive C2 reverse prenyltransferase (PT). In the biosynthesis of cytotoxic notoamide metabolites, PT NotF is responsible for catalyzing the first tailoring event of C2 reverse prenyltransfer of brevianamide F (cyclo(L-Trp-L-Pro)). Obtaining a high-resolution crystal structure of NotF (in complex with native substrate and prenyl donor mimic dimethylallyl S-thiolodiphosphate (DMSPP)) revealed a large, solvent exposed substrate binding site, intimating NotF may possess significant substrate promiscuity. To assess the full potential of NotF’s broad substrate selectivity, we synthesized a panel of 30 tryptophanyl DKPs with a suite of sterically and electronically differentiated amino acids, which were selectively prenylated by NotF in often synthetically useful conversions (2 to >99%). Quantitative representation of this substrate library enabled the development of a descriptive statistical model that provided insight into the origins of NotF’s substrate promiscuity. Through this unique approach for understanding enzyme scope, we identified key substrate descriptors such as electrophilicity, size, and flexibility, that govern enzymatic turnover by NotF. Additionally, we demonstrated the ability to couple NotF-catalyzed prenyltransfer with oxidative cyclization using recently characterized flavin monooxygenase, BvnB, from the brevianamide biosynthetic pathway. This one-pot, in vitro biocatalytic cascade proceeds with exceptional substrate recognition, and enabled the first chemoenzymatic synthesis of the marine fungal natural product, (–)-eurotiumin A, in three steps and 60% overall yield.

scholarly journals Relationship between Antimalarial Activity and Heme Alkylation for Spiro- and Dispiro-1,2,4-Trioxolane Antimalarials

2008 ◽  
Vol 52 (4) ◽  
pp. 1291-1296 ◽  
Author(s):  
Darren J. Creek ◽  
William N. Charman ◽  
Francis C. K. Chiu ◽  
Richard J. Prankerd ◽  
Yuxiang Dong ◽  
...  
Keyword(s):  
Mechanism Of Action ◽  
Antimalarial Activity ◽  
Biologically Active ◽  
Radical Intermediate ◽  
Reaction Conditions ◽  
Artemisinin Derivatives ◽  
Major Reaction Product ◽  
Major Reaction ◽  
Insight Into

ABSTRACT The reaction of spiro- and dispiro-1,2,4-trioxolane antimalarials with heme has been investigated to provide further insight into the mechanism of action for this important class of antimalarials. A series of trioxolanes with various antimalarial potencies was found to be unreactive in the presence of Fe(III) hemin, but all were rapidly degraded by reduced Fe(II) heme. The major reaction product from the heme-mediated degradation of biologically active trioxolanes was an alkylated heme adduct resulting from addition of a radical intermediate. Under standardized reaction conditions, a correlation (R 2 = 0.88) was found between the extent of heme alkylation and in vitro antimalarial activity, suggesting that heme alkylation may be related to the mechanism of action for these trioxolanes. Significantly less heme alkylation was observed for the clinically utilized artemisinin derivatives compared to the equipotent trioxolanes included in this study.

scholarly journals The soluble ectodomain of RetC634Y inhibits both the wild-type and the constitutively active Ret

2003 ◽  
Vol 372 (3) ◽  
pp. 897-903 ◽  
Author(s):  
Laura CERCHIA ◽  
Domenico LIBRI ◽  
Maria Stella CARLOMAGNO ◽  
Vittorio de FRANCISCIS
Keyword(s):  
Molecular Basis ◽  
Multiple Endocrine Neoplasia Type ◽  
Cell System ◽  
Biologically Active ◽  
Tyrosine Kinase Receptor ◽  
Wild Type ◽  
Membrane Bound ◽  
Ret Oncogene ◽  
Insight Into

Substitution of Cys-634 in the extracellular domain of the Ret tyrosine kinase receptor causes its dimerization and activation of its transforming potential. To gain further insight into the molecular basis leading to Ret activation we purified a mutant protein consisting of the entire ectodomain of the Ret carrying a Cys-634→Tyr substitution (EC-RetC634Y). The protein is glycosylated, like the native one, and is biologically active. By using an in vitro cell system we show that EC-RetC634Y inhibits the membrane-bound receptor RetC634Y, interfering with its dimerization. Furthermore, we demonstrate that EC-RetC634Y competes with the wild-type Ret receptor for ligand binding. The results presented support the notion of the possible involvment of glial cell line-derived neurotrophic factor (GDNF) with multiple endocrine neoplasia type 2A (MEN2A) tumours, and describe a useful tool for generating molecular mimetics directed towards specific mutations of the ret oncogene.

scholarly journals Biological Activity of the Tenebrionidae Beetle Antioxidant Complex in a Murine Neurotoxic Model of Parkinson's Disease

2021 ◽  
Author(s):  
Vladimir Kovalzon ◽  
Aleksandr Ambaryan ◽  
Aleksandr Revishchin ◽  
Galina Pavlova ◽  
Ekaterina Rybalkina ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Biological Activity ◽  
Early Stage ◽  
Biologically Active ◽  
Human Neuroblastoma ◽  
Protein Nature ◽  
And Control

Abstract We have previously shown that the aqueous extract of the Ulomoides dermestoides darking beetle (the Tenebrionidae family) biomass contains a powerful complex of antioxidant substances of protein and non-protein nature. Considering the crucial role of ROS in the development of neurodegeneration, we set out to test the biological activity of this extract in a mouse neurotoxic model of Parkinson's disease. The beetle extracts were administrated continuously with food and their effects on parkinsonism caused by twice injected defoliant paraquat to experimental mice was evaluated. The motor activity of the animals was analyzed in behavioral tests using a rotarod and a vertical pole. The number of tyrosine hydroxylase-immunopositive neurons in the ventral part of the substantia nigra of the midbrains of experimental and control mice was studied by immunohistochemistry. In the model in vitro system with SH-SY5Y human neuroblastoma, the effect of the extracts on cell proliferation was examined in the absence and presence of the neurotoxin MPP+. The isolation of biologically active substances from raw biomass using cavitation effects made it possible to obtain extracts with protective properties in the model of an early stage of Parkinson's disease used in this study.

scholarly journals Preventive Activity of the Extract of the Darkling Beetle Ulomoides Dermestoides in the Diet of C57Bl/6JSTO Mice in a Neurotoxic Model of Parkinson's Disease

2021 ◽  
Author(s):  
Vladimir M. Kovalzon ◽  
Alexander V. Ambaryan ◽  
Alexander V. Revishchin ◽  
Galina V. Pavlova ◽  
Ekaterina Y. Rybalkina ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Early Stage ◽  
Biologically Active ◽  
Human Neuroblastoma ◽  
Delayed Effects ◽  
Darkling Beetle ◽  
Preventive Activity ◽  
And Control

The effect of aqueous extracts of the biomass of the adult Ulomoides dermestoides beetle on the delayed effects of the defoliant paraquat causing parkinsonism in experimental mice was evaluated. The motor activity of the animals was analyzed in behavioral tests using a rotarod and a vertical pole. The number of tyrosine hydroxylase-immunopositive neurons in the ventral part of the substantia nigra of the midbrains of experimental and control mice was studied by immunohistochemistry. In the model in vitro system with SH-SY5Y human neuroblastoma, the effect of the extracts on cell proliferation was examined in the absence and presence of the neurotoxin MPP+. The isolation of biologically active substances from raw biomass using cavitation effects made it possible to obtain extracts with protective properties in the model of an early stage of Parkinson's disease used in this study.

Microwave Induced one Pot Ugi Multicomponent Reaction of Fluoroquino lone Scaffolds: Their Biological Evaluation

2020 ◽  
Vol 07 ◽  
Author(s):  
Navin B. Patel ◽  
Rahul B. Parmar ◽  
Hetal I. Soni
Keyword(s):  
Multicomponent Reaction ◽  
Mass Spectra ◽  
Antitubercular Activity ◽  
Biological Evaluation ◽  
Biologically Active ◽  
Aspergillus Clavatus ◽  
One Pot ◽  
Concentration Method ◽  
Work Up

Microwave irradiated facile and efficient process for one pot Ugi multicomponent reaction of a novel series of fluoroquinolone scaffolds is described here. On the basis of this approach, a new route to synthesize this privileged scaffolds were designed with higher yields, a clean procedure, time efficient and simple work-up. Our aim is to develop a biologically active fluoroquinolone scaffolds by microwave induced one pot Ugi multicomponent reaction. All the synthesized molecules were characterized by IR, 1H NMR, 13C NMR, and Mass spectra. The antimicrobial activity of synthesized compounds was screened against two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), two Grampositive bacteria (Staphylococcus aureus, Streptococcus pyogenes), and three fungi (Candida albicans, Aspergillus niger, Aspergillus clavatus) utilizing the MIC (Minimal Inhibitory Concentration) method and antitubercular activity H37Rv utilizing L. J. Slope method. Some of these novel derivatives demonstrate moderate to good in vitro antibacterial, antifungal and antitubercular activities.

scholarly journals Preventive Activity of the Extract of the Darkling Beetle Ulomoides Dermestoides in the Diet of C57Bl/6JSTO Mice in a Neurotoxic Model of Parkinson's Disease

2021 ◽  
Author(s):  
Vladimir M. Kovalzon ◽  
Alexander V. Ambaryan ◽  
Alexander V. Revishchin ◽  
Ekaterina Y. Rybalkina ◽  
Alexander I. Bastrakov ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Early Stage ◽  
Biologically Active ◽  
Human Neuroblastoma ◽  
Delayed Effects ◽  
Darkling Beetle ◽  
Preventive Activity ◽  
And Control

The effect of aqueous extracts of the biomass of the adult beetle Ulomoides dermestoides on the delayed effects of defoliant paraquat causing parkinsonism in experimental mice was evaluated. The motor activity of the animals was analyzed in behavioral tests using a rotarod and a vertical pole. The number of tyrosine hydroxylase-immunopositive neurons in the ventral part of the substantia nigra of the midbrain of experimental and control mice were studied by immunohistochemistry. In the model in vitro system with SH-SY5Y–human neuroblastoma, the effect of the extracts on cell proliferation was examined in the absence and in the presence of the neurotoxin MPP+. The isolation of biologically active substances from raw biomass using cavitation effects made it possible to obtain extracts with protective properties in the model of an early stage of Parkinson's disease used.

scholarly journals Facile One-Pot Synthesis of Benzo[h]isoquinolines via Strong Acid Triggered [1,2]-Sigmatropic Rearrangement: A Theoretical and Experimental Studies

2019 ◽  
Vol 31 (9) ◽  
pp. 2133-2138
Author(s):  
V.M. Boitsov ◽  
N.A. Knyazev ◽  
S.V. Shmakov ◽  
S.Yu. Vyazmin ◽  
D.M. Nikolaev ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Experimental Studies ◽  
Strong Acid ◽  
Sigmatropic Rearrangement ◽  
Biologically Active ◽  
One Pot ◽  
One Pot Synthesis ◽  
Rearrangement Reaction ◽  
Isoquinoline Derivatives

Benzo[h]isoquinoline scaffold is of interest as a rigid subunit that can be useful for constructing biologically active products. However, no good-yielded synthetic pathway to this ring system has been reported yet. Herein, a facile one-pot synthesis from N-aryl itaconimides and 1,3-diarylisobenzofuran via strong acid triggered skeletal rearrangement reaction is described. Theoretical study for this rearrangement is provided at M11/cc-pVDZ level of theory. Antitumor activity of obtained benzo[h]isoquinoline derivatives against human erythroleukemia K562 cell line was evaluated in vitro by MTS-assay.

Care for delirium superimposed on dementia at an early stage

2020 ◽  
Keyword(s):  
Behavioral Problems ◽  
Healthcare Professionals ◽  
Early Stage ◽  
Good Care ◽  
Structured Interviews ◽  
Ethical Considerations ◽  
Appropriate Care ◽  
Adequate Care ◽  
Insight Into ◽  
Delirium Superimposed On Dementia

Delirium is a common serious complication in dementia that is associated with poor prognosis and a high burden on caregivers and healthcare professionals. Appropriate care is therefore important at an early stage for patients with delirium superimposed on dementia To gain insight into the care of six patients with delirium superimposed on dementia, 19 semi-structured interviews were conducted focused on the experiences of caregivers and professionals. The interviews revealed four themes that appeared to play a role: 1. experiences with and views on behavioral problems of these patients, 2. recognition and diagnosis of delirium in dementia, 3. views on good care and 4. organizational aspects. Knowledge gaps about delirium in dementia, as well as ethical considerations, play an important role in organizing timely and adequate care for patients with delirium superimposed on dementia.

Properties and Biotechnological Application of mutant Derivatives of Mini-intein PRP8 from Penicillium chrysogenum with Improved Control of C-terminal Processing

2019 ◽  
Vol 35 (6) ◽  
pp. 91-101
Author(s):  
F.A. Klebanov ◽  
S.E. Cheperegin ◽  
D.G. Kozlov
Keyword(s):  
Penicillium Chrysogenum ◽  
Protein Denaturation ◽  
Biologically Active ◽  
Cultivation Temperature ◽  
Target Proteins ◽  
E Coli ◽  
Complete Inactivation ◽  
Target Molecules ◽  
Proteins And Peptides

Mutant variants of mini-intein PRP8 from Penicillium chrysogenum (Int4b) with improved control of C-terminal processing were characterized. The presented variants can serve as a basis for self-removed polypeptide tags capable of carrying an affine label and allowing to optimize the process of obtaining target proteins and peptides in E. coli cells. They allow to synthesize target molecules in the composition of soluble and insoluble hybrid proteins (fusions), provide their afnne purification, autocatalytic processing and obtaining mature target products. The presented variants have a number of features in comparison with the known prototypes. In particular the mutant mini-intein Int4bPRO, containing the L93P mutation, has temperature-dependent properties. At cultivation temperature below 30 °C it allows the production of target molecules as part of soluble fusions, but after increasing of cultivation temperature to 37 °C it directs the most of synthesized fusions into insoluble intracellular aggregates. The transition of Int4bPRO into insoluble form is accompanied by complete inactivation of C-terminal processing. Further application of standard protein denaturation-renaturation procedures enable efficiently reactivate Int4bPRO and to carry out processing of its fusions in vitro. Two other variants, Int4b56 and Int4b36, containing a point mutation T62N or combination of mutations D144N and L146T respectively, have a reduced rate of C-terminal processing. Their use in E. coli cells allows to optimize the biosynthesis of biologically active target proteins and peptides in the composition of soluble fusions, suitable for afnne purification and subsequent intein-dependent processing without the use of protein denaturation-renaturation procedures. intein, fusion, processing, processing rate, gelonin The work was supported within the framework of the State Assignment no. 595-00003-19 PR.

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