Copper-Catalyzed Azide-Alkyne Cycloaddition (CuAAC)-Mediated Macrocyclization of Peptides: Impact on Conformation and Biological Activity

2018 ◽  
Vol 18 (7) ◽  
pp. 591-610 ◽  
Author(s):  
Chiara Testa ◽  
Anna Maria Papini ◽  
Michael Chorev ◽  
Paolo Rovero

The long-lasting impetus to design novel modes of macrocyclization, and their implementation into a wide range of bioactive peptides, originates from their contributions to the restriction of conformational space and the stabilization of preferential bioactive conformations that support higher efficacy and binding affinity to cognate macromolecular targets, improved specificity and lowering susceptibility to enzymatic degradation processes. Introducing CuI-catalyzed azide-alkyne cycloaddition (CuAAC), a prototypical click reaction, to the field of peptide sciences as a bio-orthogonal reaction that generates a disubstituted-[1,2,3]triazol-1-yl moiety as a pseudopeptidic bond that is peptidomimetic in nature, paved the way to its widespread application as a new and promising mode of macrocyclization. This review presents the state-of-art of CuAAC-mediated macrocyclization as it applies to an expansive range of bioactive peptides and explores the relationship among the structural diversity of CuAACmediated cyclizations, biological activities and conformations.

1998 ◽  
Vol 44 (12) ◽  
pp. 1115-1136 ◽  
Author(s):  
M J Butler ◽  
A W Day

The relationship of polyketide melanogenesis molecular biology to that of nonmelanin-producing pathways in a wide range of fungi and other organisms is discussed. Analytical methods and fundamental properties of melanins are discussed and fungal melanin properties are compared with those of animal and bacterial melanins. The enzymatic degradation of melanins by lignin peroxidases is described.Key words: fungal melanin, polyketide melanin, DHN melanin, melanin degradation, melanin properties, melanin analysis.


Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2095 ◽  
Author(s):  
Yi Qiu ◽  
Wen-Jian Lan ◽  
Hou-Jin Li ◽  
Liu-Ping Chen

Linear triquinane sesquiterpenoids represent an important class of natural products. Most of these compounds were isolated from fungi, sponges, and soft corals, and many of them displayed a wide range of biological activities. On account of their structural diversity and complexity, linear triquinane sesquiterpenoids present new challenges for chemical structure identification and total synthesis. 118 linear triquinane sesquiterpenoids were classified into 8 types, named types I–VIII, based on the carbon skeleton and the position of carbon substituents. Their isolation, structure elucidations, biological activities, and chemical synthesis were reviewed. This paper cited 102 articles from 1947 to 2018.


2004 ◽  
Vol 1 (4) ◽  
pp. 206-210 ◽  
Author(s):  
M. B. Deshmukh ◽  
A. R. Mulik ◽  
Savita Dhongade-Desai

The increase in the internal diameter of a blood vessel that results from relaxation of smooth muscle within the wall of the vessel is vasodilation. This causes an increase in blood flow and a decrease in systemic vascular resistance. Some substances produced by tissue deprived of fresh blood seem to be responsible for the dilation. Many products of metabolism bring about the action, CO2and acids are among them. Dilation of vessels is necessary to restore local environment of tissues and normal metabolism. It may prove to be potential in the treatment of different cardiac disorders like atherosclerosis, where, the blood vessels are narrowed due to deposition of plaque of substances like cholesterol etc. 1,4-benzothiazines have been reported to possess wide range of pharmacological and biological activities. Here, we report the synthesis and biological activity of some new arylidenehydrazino-(1H)-1,4-benzothiazines. The synthesized compounds were subjected to a prediction of biological activities. A software application (PASS) was used for this purpose. The relationship between structure and different biological activities was studied and it was found that the arylidenehydrazino-(1H)-1,4-benzothiazines are expected to be potential vasodilators.


Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5922
Author(s):  
Constanze Paulus ◽  
Josef Zapp ◽  
Andriy Luzhetskyy

Peptide natural products displaying a wide range of biological activities have become important drug candidates over the years. Microorganisms have been a powerful source of such bioactive peptides, and Streptomyces have yielded many novel natural products thus far. In an effort to uncover such new, meaningful compounds, the metabolome of Streptomyces acidiscabies was analyzed thoroughly. Three new compounds, scabimycins A–C (1–3), were discovered, and their chemical structures were elucidated by NMR spectroscopy. The relative and absolute configurations were determined using ROESY NMR experiments and advanced Marfey’s method.


2020 ◽  
Vol 26 (1) ◽  
pp. 138-159 ◽  
Author(s):  
Yanfei Ban ◽  
Tianshuang Xia ◽  
Rui Jing ◽  
Yaoli Guo ◽  
Yiya Geng ◽  
...  

Plants of the genus Vitex (Verbenaceae) are mainly distributed throughout tropical and temperate regions, and many Vitex plants have been traditionally used in folk medicine. Plants of this genus are a rich source of diterpenoids, which not only displayed versatile structural diversity with potential chemotaxonomical significance but also exhibited a wide range of biological activities, mainly including in vitro cytotoxic, antiinflammatory, antimicrobial, hormone level-regulating and antiangiogenic activities. Recently, a series of bioactive diterpenoids, with interesting carbon skeletons, have been reported and gathered considerable interest. This article systematically reviewed diterpenoids isolated from the genus Vitex that appeared in the literature up to December 2018, critically highlighting their structural diversity and pharmacological activities. Up to now, a total of 154 diterpenoids with diverse structures have been isolated and identified from Vitex plants. The authors also summarized the reported structure-activity relationships of those well explored Vitex diterpenoids. Finally, the authors discussed the challenges and potential applications of these diterpenoids in the future.


Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 912
Author(s):  
Constantijn Raaymakers ◽  
Benoit Stijlemans ◽  
Charlotte Martin ◽  
Shabnam Zaman ◽  
Steven Ballet ◽  
...  

A wide range of frogs produce skin poisons composed of bioactive peptides for defence against pathogens, parasites and predators. While several frog families have been thoroughly screened for skin-secreted peptides, others, like the Microhylidae, have remained mostly unexplored. Previous studies of microhylids found no evidence of peptide secretion, suggesting that this defence adaptation was evolutionarily lost. We conducted transcriptome analyses of the skins of Phrynomantis bifasciatus and Phrynomantis microps, two African microhylid species long suspected to be poisonous. Our analyses reveal 17 evolutionary related transcripts that diversified from to those of cytolytic peptides found in other frog families. The 19 peptides predicted to be processed from these transcripts, named phrynomantins, show a striking structural diversity that is distinct from any previously identified frog skin peptide. Functional analyses of five phrynomantins confirm the loss of a cytolytic function and the absence of insecticidal or proinflammatory activity, suggesting that they represent an evolutionary transition to a new, yet unknown function. Our study shows that peptides have been retained in the defence poison of at least one microhylid lineage and encourages research on similarly understudied taxa to further elucidate the diversity and evolution of skin defence molecules.


Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 4019
Author(s):  
Douglas Kemboi ◽  
Xolani Peter ◽  
Moses Langat ◽  
Jacqueline Tembu

The genus Euphorbia is one of the largest genera in the spurge family, with diversity in range, distribution, and morphology. The plant species in this genus are widely used in traditional medicine for the treatment of diseases, ranging from respirational infections, body and skin irritations, digestion complaints, inflammatory infections, body pain, microbial illness, snake or scorpion bites, pregnancy, as well as sensory disorders. Their successes have been attributed to the presence of diverse phytochemicals like polycyclic and macrocyclic diterpenes with various pharmacological properties. As a result, Euphorbia diterpenes are of interest to chemists and biochemists with regard to drug discovery from natural products due to their diverse therapeutic applications as well as their great structural diversity. Other chemical constituents such as triterpenoids have also been reported to possess various pharmacological properties, thus supporting the traditional uses of the Euphorbia species. These triterpenoids can provide potential leads that can be developed into pharmaceutical compounds for a wide range of medicinal applications. However, there are scattered scientific reports about the anticancer activities of these constituents. Harnessing such information could provide a database of bioactive pharmacopeia or targeted scaffolds for drug discovery. Therefore, this review presents an updated and comprehensive summary of the ethnomedicinal uses, phytochemistry, and the anticancer activities of the triterpenoids of Euphorbia species. Most of the reported triterpenoids in this review belong to tirucallane, cycloartanes, lupane, oleanane, ursane, and taraxane subclass. Their anticancer activities varied distinctly with the majority of them exhibiting significant cytotoxic and anticancer activities in vitro. It is, therefore, envisaged that the report on Euphorbia triterpenoids with interesting anticancer activities will form a database of potential leads or scaffolds that could be advanced into the clinical trials with regard to drug discovery.


Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1842 ◽  
Author(s):  
Yue-Xian Jin ◽  
Lei-Ling Shi ◽  
Da-Peng Zhang ◽  
Hong-Yan Wei ◽  
Yuan Si ◽  
...  

Natural daphnane diterpenoids, mainly distributed in plants of the Thymelaeaceae and Euphorbiaceae families, usually include a 5/7/6-tricyclic ring system with poly-hydroxyl groups located at C-3, C-4, C-5, C-9, C-13, C-14, or C-20, while some special types have a characteristic orthoester motif triaxially connectedat C-9, C-13, and C-14. The daphnane-type diterpenoids can be classified into five types: 6-epoxy daphnane diterpenoids, resiniferonoids, genkwanines, 1-alkyldaphnanes and rediocides, based on the oxygen-containing functions at rings B and C, as well as the substitution pattern of ring A. Up to now, nearly 200 daphnane-type diterpenoids have been isolated and elucidated from the Thymelaeaceae and Euphorbiaceae families. In-vitro and in-vivo experiments of these compounds have shown that they possess a wide range of biological activities, including anti-HIV, anti-cancer, anti-leukemic, neurotrophic, pesticidal and cytotoxic effects. A comprehensive account of the structural diversity is given in this review, along with the cytotoxic activities of daphnane-type diterpenoids, up to April 2019.


2014 ◽  
Vol 70 (a1) ◽  
pp. C1296-C1296
Author(s):  
Jacqueline Cherfils

The International Year of Crystallography coincides with the celebration of the 50th anniversary of the landmark articles on allostery by Monod, Changeux & Jabob (1963) and Monod, Wyman and Changeux (1965). These articles defined "allosteric" interactions in proteins as "indirect interactions between topographically distinct sites" and devised the model (now known as the MWC model) for the conformational changes mediating them. The concept, which Jacques Monod reportedly described as the "second secret of life" second only to the genetic code, was invented to account for feedback inhibition and cooperativity properties in enzymes and regulatory proteins, including hemoglobin. The pioneering crystallographic analysis of hemoglobin, whose structure had been determined by Max Perutz at about the same time, provided evidence for the concept and likely contributed to inspire it. Half a century later, allosteric interactions and underlying conformational transitions have been captured in many crystallographic structures, uncovering a wide range of mechanisms whereby information that affects biological activities is propagated over a long distance between two binding sites. I will present examples of allostery in protein crystallographic structures that illustrate the expansion and widespread application of the original concept, notably in understanding diseases and aiding in drug design.


2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Đenđi Vaštag ◽  
Suzana Apostolov ◽  
Borko Matijević ◽  
Jelena Nakomčić ◽  
Aleksandar Marinković

Phenylacetamide derivatives are a group of compounds that exhibit a wide range of biological activities as analgetic, anticonvulsant, pesticide, cytostatic. It is well known that the biological activity and the field of activity of the substance are greatly dependent on its physical, chemical and structural properties. In this paper, we applied QSRR analysis (Quantitative Structure Retention Relationships), which is based on the prediction of biological properties of compounds based on their chromatographic retention behaviors. To that end, retention constants of investigated N-substituted-2-phenylacetamide were determined by reversed phase thin-layer chromatography, (HPTLC RP18 F254s) in the presence of different volume fractions of n-propanol and tetrahydrofuran. The resulting data were correlated with molecular descriptors determined in different ways in order to establish the mathematical model that describes the relationship between retention properties and biological activities of investigated phenylacetamides.


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