Discovery of unguisin J, a new cyclic peptide from Aspergillus heteromorphus CBS 117.55, and phylogeny-based bioinformatic analysis of UngA NRPS domains

• Sharmila Neupane,
• Marcelo Rodrigues de Amorim and
• Elizabeth Skellam

Beilstein J. Org. Chem. 2024, 20, 321–330, doi:10.3762/bjoc.20.32

• de São Paulo, CP 780, CEP 13560-970, São Carlos, SP, Brazil 10.3762/bjoc.20.32 Abstract Several under-explored Aspergillus sp. produce intriguing heptapeptides containing a γ-aminobutyric acid (GABA) residue with as yet unknown biological functions. In this study, a new GABA-containing heptapeptide

• of the UngA NRPS were analyzed in an attempt to understand the lack of substrate specificity observed. Keywords: adenylation domain; condensation domain; fungal non-ribosomal peptide synthetase; heptapeptide; unguisin biosynthesis; Introduction Unguisins are a small family of fungal cyclic

¹⁹F NMR as a tool in chemical biology

• Diana Gimenez,
• Aoife Phelan,
• Cormac D. Murphy and
• Steven L. Cobb

Beilstein J. Org. Chem. 2021, 17, 293–318, doi:10.3762/bjoc.17.28

• acids carrying novel fluorine-based functionalities such as -SF5 has also recently achieved considerable interest. For instance, the work carried out within the Welch group, who reported the synthesis and NMR conformational characterization of the first heptapeptide containing a pentafluorosulfanylated

Efficiency Eff_syn of complex syntheses as multicomponent reactions, its algorithm and calculations based on concrete criteria

• Heiner Eckert

Beilstein J. Org. Chem. 2019, 15, 1425–1433, doi:10.3762/bjoc.15.142

• to form a linear decapeptide (Scheme 4b); sequential synthesis of two non-identical peptides (1 heptapeptide and 1 tripeptide) and their linking to form a linear decapeptide (Scheme 4c); Calculation by means of the algorithm The results are impressive. A up to 2.5-fold yield can be achieved depending

Recyclable hypervalent-iodine-mediated solid-phase peptide synthesis and cyclic peptide synthesis

• Dan Liu,
• Ya-Li Guo,
• Jin Qu and
• Chi Zhang

Beilstein J. Org. Chem. 2018, 14, 1112–1119, doi:10.3762/bjoc.14.97

• ) reagent FPID and (4-MeOC6H4)3P was successfully applied to solid-phase peptide synthesis and cyclic peptide synthesis. Four peptides with biological activities were synthesized through SPPS and the bioactive cyclic heptapeptide pseudostellarin D was obtained via solution-phase peptide synthesis. It is

• -enkephalin 1 (Table 1, entry 1) could be successfully synthesized following the route mentioned above (Scheme 2). Besides, the precursor 2 of a cyclic heptapeptide pseudostellarin D [37][38][39] was also obtained via SPPS in good yield (Table 1, entry 2), the cyclization of 2 to give pseudostellarin D using

• -Ile-Leu), a cyclic heptapeptide named pseudostellarin D (Figure 2), is one of these cyclic peptides. Pseudostellarin D was first isolated and identified in 1994 by Itokawa and co-workers [37]. In addition, the authors reported that pseudostellarin D showed potent tyrosinase inhibitory activities. In

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

• Eirinaios I. Vrettos,
• Gábor Mező and
• Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

Recent progress in the racemic and enantioselective synthesis of monofluoroalkene-based dipeptide isosteres

• Myriam Drouin and
• Jean-François Paquin

Beilstein J. Org. Chem. 2017, 13, 2637–2658, doi:10.3762/bjoc.13.262

• diastereoisomers were separated after incorporation into the heptapeptide prior to biological studies, hence one had a D-Phe while the other had a L-Phe. The functional activity of the fluorinated mutants was evaluated by the calcium mobilizing response in GPR103-transfected cells. The peptides containing Gly-ψ[(Z

Biochemical and structural characterisation of the second oxidative crosslinking step during the biosynthesis of the glycopeptide antibiotic A47934

• Veronika Ulrich,
• Clara Brieke and
• Max J. Cryle

Beilstein J. Org. Chem. 2016, 12, 2849–2864, doi:10.3762/bjoc.12.284

• , which is generated by the actions of cytochrome P450 (Oxy) enzymes that affect the crosslinking of aromatic side chains of amino acid residues contained within the GPA heptapeptide precursor. Given the crucial role peptide cyclisation plays in GPA activity, the characterisation of this process is of

• homologues can display significantly different catalytic propensities despite their overall similarities. Keywords: crystal structure; cytochrome P450; glycopeptide antibiotic; peptide; phenolic coupling; Introduction The glycopeptide antibiotics (GPAs) are a series of highly modified heptapeptide natural

• ) this includes three and four crosslinks, respectively, which occur between the side chains of aromatic residues [3] within the parent heptapeptide (Figure 1b) [4]. This degree of crosslinking in turn renders the total synthesis of GPAs as unfeasible for production and hence both first and second

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

• Loïc Leclercq

Beilstein J. Org. Chem. 2016, 12, 2644–2662, doi:10.3762/bjoc.12.261

• authors have synthesized a heptapeptide (Lys-Thr-Gly-Asp-Arg-Gly-Phe) that mimics this binding site of thaumatin. The results show that α-CD binds to the C-terminal solvent accessible phenylalanine residue with a binding constant of 8.8 M−1. As the α-CD may interact with the active binding site on

Natural products from microbes associated with insects

• Christine Beemelmanns,
• Huijuan Guo,
• Maja Rischer and
• Michael Poulsen

Beilstein J. Org. Chem. 2016, 12, 314–327, doi:10.3762/bjoc.12.34

• application of these compounds resulted in tetanic paralysis in many insects, caused by destruxin-mediated opening of calcium channels and resulting membrane depolarization. In another study, the cyclic heptapeptide serinocyclins (e.g., serinocyclin A (42)) were isolated from conidia harvested on agar surface

Diastereoselectivity in the Staudinger reaction of pentafluorosulfanylaldimines and ketimines

• Alexander Penger,
• Cortney N. von Hahmann,
• Alexander S. Filatov and
• John T. Welch

Beilstein J. Org. Chem. 2013, 9, 2675–2680, doi:10.3762/bjoc.9.303

• exception is the inclusion of an ω-SF5-substituted amino acid incorporated at the crucial first and fourth positions of a heptapeptide [23]. When introduced at these positions, the SF5-substituted amino acid had a strong propensity to direct α-helix formation of even this short heptapeptide presumably by

Natural product biosyntheses in cyanobacteria: A treasure trove of unique enzymes

• Jan-Christoph Kehr,
• Douglas Gatte Picchi and
• Elke Dittmann

Beilstein J. Org. Chem. 2011, 7, 1622–1635, doi:10.3762/bjoc.7.191

• the cyanobacterium Microcystis aeruginosa [17][18][19]. Microcystins are produced by different genera of freshwater cyanobacteria and inhibit eukaryotic protein phosphatases of types 1 and 2A. A signature of this heptapeptide family is the unusual β-amino acid Adda (3-amino-9-methoxy-2,6,8-trimethyl

• for the terrestrial cyanobacterium Nostoc sp. ATCC 53789 [55]. The cyclic heptapeptide shares the L-4-methylproline unit of nostopeptolides and is synthesized by two enzymes closely resembling NosE and NosF. A unique feature of nostocyclopeptide biosynthesis is the mechanism of macrocyclization

The C–F bond as a conformational tool in organic and biological chemistry

• Luke Hunter

Beilstein J. Org. Chem. 2010, 6, No. 38, doi:10.3762/bjoc.6.38

• 65. The electron-withdrawing trifluoromethyl group of 65 disrupts a key hydrogen bond, leading to a different conformation as determined by NOESY experiments. The C–F bond influences the conformation of β-peptides. β-Heptapeptide 66 adopts a helical conformation, reinforced by the α-fluoroamide

• effect and a fluorine-amide gauche alignment. In isomeric β-heptapeptide 67, the helical conformation is disrupted by the fluorine atom. The disruptive effect of fluorine is overridden in the longer helix-forming β-tridecapeptide 68. The conformations of pseudopeptides 69 and 70 are influenced by the α

The first preparative solution phase synthesis of melanotan II

• Vladimir V. Ryakhovsky,
• Georgy A. Khachiyan,
• Nina F. Kosovova,
• Elena F. Isamiddinova and
• Andrey S. Ivanov

Beilstein J. Org. Chem. 2008, 4, No. 39, doi:10.3762/bjoc.4.39

• Vladimir V. Ryakhovsky Georgy A. Khachiyan Nina F. Kosovova Elena F. Isamiddinova Andrey S. Ivanov R&D Dept., Pharm-Sintez, 38 Shosse Entusiastov, 111123 Moscow, Russia 10.3762/bjoc.4.39 Abstract Melanotan II is a synthetic cyclic heptapeptide used to prevent a sunlight-induced skin cancer by

• approach to this important therapeutical heptapeptide in full detail. Special attention is paid to minimum orthogonal protection of lateral functional groups to achieve maximum atom [7][8] and step [9] economy. α-Melanocyte stimulating hormone (α-MSH, α-melanotropin) is a linear tridecapeptide of the

• 55–60% overall yield [18][24]. The yield dropped to 30% when lactamization of the linear heptapeptide sequence, synthesized on the resin, was performed in DMF solution using DPPA/K2HPO4. Despite the high overall yield in the described solid phase approach, it has several drawbacks for the scale-up