Molecular tweezer–peptide conjugates disrupt the protein–protein interaction between survivin and histone H3 essential in mitosis

• Catherine Gsell,
• Philipp Rebmann,
• Karina Opara,
• Christine Beuck,
• Peter Bayer,
• David Bier,
• Ingrid R. Vetter and
• Thomas Schrader

Beilstein J. Org. Chem. 2026, 22, 557–567, doi:10.3762/bjoc.22.41

• Pro26, corresponding to a previously unknown binding mode. Guided by the accessibility of survivin’s lysine residues in the CPC, a number of new promising peptide tweezers was synthesized, able to connect both binding sites on the protein. Keywords: click reaction; chromosomal passenger complex

• ; protein–protein interaction; mitosis; X-ray crystallography; Introduction The fundamental process of mitosis is controlled by a very large protein complex called the kinetochore, formed by self-assembly from hundreds of single protein components [1]. For the intricate regulation of the various phases of

• centromere protein), and the kinase Aurora B. During mitosis, Aurora B phosphorylates important components of the kinetochore and thus exerts control over key events of the whole process. The other three proteins localize the CPC during the different mitotic phases [4]. Survivin, borealin and INCENP are

Synthesis of a HDAC inhibitor–nanogold probe for cryo-EM visualization in class I HDAC co-repressor complexes

• Wiktoria A. Pytel,
• John W. R. Schwabe and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2026, 22, 480–485, doi:10.3762/bjoc.22.35

• III [3]. HDAC1, HDAC2, and HDAC3 of the class I HDACs exist in multiprotein co-repressor complexes in vivo [4]. HDAC1 and HDAC2 exist interchangeably in the CoREST, MIDAC, SIN3, NuRD, MIER, and RERE complexes, while HDAC3 exists in the SMRT/NCoR complex [4]. The protein complex partners govern the

• complex is critical, as it may significantly influence how CoREST engages with nucleosomal substrates. Nanogold particles (1–5 nm in diameter) are highly electron-dense and provide high contrast in microscopy. They have been successfully applied in immunogold electron microscopy to study protein

• on a Titan Krios microscope. A range of protein particles resembling the CoREST ternary complex were observed, with several displaying a distinct “black dot” indicative of the electron-dense gold nanoparticle (Figure S6 in Supporting Information File 1). However, as expected, Au–(CI-994) was not

Structural reassignment of compound 968, an allosteric glutaminase inhibitor

• Lindsey A. Albertelli,
• Sainabou Jallow,
• Chun Li and
• Scott M. Ulrich

Beilstein J. Org. Chem. 2026, 22, 455–460, doi:10.3762/bjoc.22.33

• of wash buffer supplemented with 10 mM imidazole. Protein was eluted into 1 mL fractions at 4 °C with wash buffer supplemented with 300 mM imidazole. A 20 µL aliquot of each fraction was analyzed by SDS-PAGE. Fractions with pure protein were pooled and the buffer was changed to 20 mM Tris (pH 8.5

Synthesis and anti-cancer activity of naphthalimide–organylselanyl conjugates

• Rajkumar Ravi and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2026, 22, 416–435, doi:10.3762/bjoc.22.29

• cancer cell line. Molecular docking simulation revealed strong binding interaction and affinities towards the tyrosine kinase domain of epidermal growth factor receptor (EGFR), and the protein–ligand interaction resembles the interaction found in the co-crystallised protein–erlotinib complex. Result and

• -covalent interactions with the target protein, has a significant impact on their anticancer potential. The binding interactions of compounds 7 and 8 with the active (1M17) and inactive (4JHO) EGFR tyrosine kinase domain are summarised in Table 2. The ligand structure of compound 7 was obtained from a

• and 8 with the active (1M17) tyrosine kinase domain of EGFR The epidermal growth factor receptor (EGFR) of the active tyrosine kinase domain in complex with erlotinib was retrieved from the Protein Data Bank (PDB ID: 1M17, https://doi.org/10.2210/pdb1M17/pdb, [71]) and subjected to molecular docking

Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities

• Ilia Korniltsev,
• Vasily Bazhenov,
• Alexander Gorbunov,
• Dmitry Cheshkov,
• Stanislav Bezzubov,
• Vladimir Kovalev and
• Ivan Vatsouro

Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28

• ]. (Multi)calix[4]arenes having (dialkyl)amino groups at the wide rims are soluble in aqueous media at physiological pHs and may be used in protein sensing [18], DNA binding/recognition [19][20][21][22][23], and cell transfection [24][25][26]. Their water-soluble guanidinium derivatives are also

Design, synthesis and biological evaluation of 2,5-diaryloxazolo[4,5-d]pyrimidin-7-ylamines as selective cytotoxic agents against HeLa cells

• Maryna V. Kachaeva,
• Agnieszka B. Olejniczak,
• Marta Denel-Bobrowska,
• Victor V. Zhirnov,
• Yevheniia S. Velihina,
• Stepan G. Pilyo and
• Volodymyr S. Brovarets

Beilstein J. Org. Chem. 2026, 22, 390–398, doi:10.3762/bjoc.22.27

• (Table 3). With regard to the substrate specificity of Pgp, it is highly probable that these compounds are not substrates of this protein, although compounds 1 and 7, unlike 9, appear to be capable of inhibiting it (Table 3). A low probability of oxidative metabolism of these compounds by the studied

Ring contraction and ring expansion reactions in terpenoid biosynthesis and their application to total synthesis

• Nicolas Kratena,
• Nicolas Heinzig and
• Peter Gärtner

Beilstein J. Org. Chem. 2026, 22, 289–343, doi:10.3762/bjoc.22.21

• the groups of Collado, Cane and Viaud could identify a protein titled BcBOT2 (= Botrytiscinerea BOTrydial) with similarity to microbial terpene synthases [78]. Starting from farnesyl pyrophosphate (9) BcBOT2 catalyses a rare, formal [2 + 2] cycloaddition to form the cyclobutyl carbenium ion 29a which

Spirobarbiturates with a pyrrolizidine moiety: synthesis, structure and biological evaluation

• Arthur A. Puzyrkov,
• Andrew S. Drachuk,
• Ekaterina A. Popova,
• Alexander V. Stepakov and
• Vitali M. Boitsov

Beilstein J. Org. Chem. 2026, 22, 274–288, doi:10.3762/bjoc.22.20

• inhibition of hERG in vitro. The results are shown in Supporting Information File 1, Table S5. As can be seen from the table, the obtained results suggest that the compounds have a good intestinal absorption and medium permeability. However they are expected to have low plasma protein binding and permeation

• results obtained, docking simulations were performed for the possible interaction of spiro-adducts with actin, as the most widespread and highly conserved cellular protein. Since the initial determination of the G-actin crystal structure in complex with DNase I, many actin structures have been registered

• and nucleotide, DNaze I-binding). The structure of the 8DNH protein was retrieved from the protein data bank and the Molegro Virtual Docker 6.0 software was used to prepare it for the docking study [66][67]. The pose organizer and the ligand energy inspector tool were used to examine the docking

Conformational analysis of difluoromethylornithine: factors influencing its gas-phase and bioactive conformations

• Matheus P. Freitas

Beilstein J. Org. Chem. 2026, 22, 237–243, doi:10.3762/bjoc.22.17

• )/CBS level of theory. Color labels: H = white, C = grey, N = blue, O = red, F = electric blue. (S)-DFMO bound within the active site of human arginase I obtained from the Protein Data Bank (3GN0) (https://doi.org/10.2210/pdb3gn0/pdb, [21]). Dotted lines represent hydrogen-bonding interactions with

Synthesis of diaryl phosphates using phytic acid as a phosphorus source

• Kazuya Asao,
• Seika Matsumoto,
• Haruka Mori,
• Riku Yoshimura,
• Takeshi Sasaki,
• Naoya Hirata,
• Yasuyuki Hayakawa and
• Shin-ichi Kawaguchi

Beilstein J. Org. Chem. 2026, 22, 213–223, doi:10.3762/bjoc.22.15

• first delipidated with n-hexane. Phytic acid was extracted with 1 M HCl for 1 h. After extraction, the pH value was adjusted to 4.5 with 8.0 M NaOH, which is the isoelectric point of rice bran protein. Solids were removed via filtration and centrifugation followed by supernatant collection. The phytate

Thiazolidinones: novel insights from microwave synthesis, computational studies, and potentially bioactive hybrids

• Luan A. Martinho,
• Victor H. J. G. Praciano,
• Guilherme D. R. Matos,
• Claudia C. Gatto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2025, 21, 2618–2636, doi:10.3762/bjoc.21.203

• ]. Some rhodanine-based derivatives act as inhibitors of hepatitis C virus (HCV) protease [19], UDP-N-acetylmuramate/ʟ-alanine ligase [20], histidine decarboxylase [21], aldose/aldehyde reductase [22], fungal protein mannosyl transferase 1 (PMT1) [23], metallo β-lactamase [24], cathepsin D [25], JNK

Synthesis and characterization of a isothiouronium-calix[4]arene derivative: self-assembly and anticancer activity

• Giuseppe Granata,
• Loredana Ferreri,
• Claudia Giovanna Leotta,
• Giovanni Mario Pitari and
• Grazia Maria Letizia Consoli

Beilstein J. Org. Chem. 2025, 21, 2535–2541, doi:10.3762/bjoc.21.195

• class of interest in the search for new chemotherapeutic agents. They are known inhibitors of protein kinase C [40] and agonists of the GABA-type [41] and histamine-H3 receptors [42]. S-Allylic isothiouronium salts substituted with aliphatic groups have shown to combine high antitumor activity against

Effect of a photoswitchable rotaxane on membrane permeabilization across lipid compositions

• Udyogi N. K. Conthagamage,
• Lilia Lopez,
• Zuliah A. Abdulsalam and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2498–2512, doi:10.3762/bjoc.21.192

• bacteria or malignant cells like cancer) [5][6], or to influence membrane protein function and thereby control cellular behavior [7][8]. One promising approach is the development of light-activated molecules that can modulate membrane properties upon irradiation, enabling remote activation with high

Assembly strategy for thieno[3,2-b]thiophenes via a disulfide intermediate derived from 3-nitrothiophene-2,5-dicarboxylate

• Roman A. Irgashev

Beilstein J. Org. Chem. 2025, 21, 2489–2497, doi:10.3762/bjoc.21.191

• developed for photothermal and photodynamic therapy, where their π-conjugated frameworks contribute to both imaging and therapeutic functions [19]. Some other TT-based compounds have been reported to inhibit specific carbonic anhydrase isoforms [20], protein tyrosine phosphatase 1B [21], as well as to act

Comparative analysis of complanadine A total syntheses

• Reem Al-Ahmad and
• Mingji Dai

Beilstein J. Org. Chem. 2025, 21, 2334–2344, doi:10.3762/bjoc.21.178

• glial cells, rendering complanadine A a promising lead compound for neurological disorder treatment. Later, complanadine A was also identified as a lead compound for pain management by Siegel and co-workers [8]. They discovered one of its potential cellular targets as the Mas-related G protein-coupled

Enantioselective radical chemistry: a bright future ahead

• Anna C. Renner,
• Sagar S. Thorat,
• Hariharaputhiran Subramanian and
• Mukund P. Sibi

Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174

• selective synthesis owing to their unprecedented catalytic activity and selectivity. Advances in the field of protein engineering have made enzymatic catalysis more amenable to enantioselective organic synthesis in the past decade. Recent advances in the development of synergistic catalytic systems

Research towards selective inhibition of the CLK3 kinase

• Vinay Kumar Singh,
• Frédéric Justaud,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Blandine Baratte,
• Thomas Robert,
• Stéphane Bach,
• Chada Raji Reddy,
• Nicolas Levoin and
• René L. Grée

Beilstein J. Org. Chem. 2025, 21, 2250–2259, doi:10.3762/bjoc.21.172

• VS-77 which has now a significant affinity toward CLK3 (IC50 = 0.3 μM). Thus, VS-77 appears as a new pan-inhibitor of the CLK family. Keywords: cancer; CLK3; kinases; molecular modelling; quinazolines; triazoles; Introduction Human protein kinases are a family comprising nearly 535

• phosphotransferases (called the human kinome) involved in specific signaling pathways which regulate cell functions (e.g., metabolism, cell cycle progression, cell adhesion, vascular function, and angiogenesis). Therefore, the dysregulation of protein kinase enzymatic activity, induced by genetic alterations as well

• as overexpression, is implicated in the pathogenesis of numerous deleterious diseases including nervous and inflammatory disorders as well as a number of malignancies [1][2][3]. Kinases are also known to be highly druggable by both allosteric and competitive inhibitors. As a consequence, protein

Thiadiazino-indole, thiadiazino-carbazole and benzothiadiazino-carbazole dioxides: synthesis, physicochemical and early ADME characterization of representatives of new tri-, tetra- and pentacyclic ring systems and their intermediates

• Gyöngyvér Pusztai,
• László Poszávácz,
• Anna Vincze,
• András Marton,
• Ahmed Qasim Abdulhussein,
• Judit Halász,
• András Dancsó,
• Gyula Simig,
• György Tibor Balogh and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169

• microsome (HLM) fractions were thawed on ice and diluted in 0.05 M potassium phosphate buffer (pH 7.4) to a final protein concentration of 1.25 mg/mL. Test compounds were dissolved in DMSO to create stock solutions of 5 mM. The drug concentration in the final assays was 10 μM. The assay was performed in

• conditions using Equation 5: where the HLM protein per gram of liver was equal to 25 and the liver weight per standard body was equal to 49. Testosterone was included as a positive control to confirm metabolic competence of the HLM fractions, with and without cofactors. Zero-time samples served as 100

Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings

• Lifen Peng,
• Ting Wang,
• Zhiwen Yuan,
• Bin Li,
• Zilong Tang,
• Xirong Liu,
• Hui Li,
• Guofang Jiang,
• Chunling Zeng,
• Henry N. C. Wong and
• Xiao-Shui Peng

Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166

• F and cryptotrione have fused and spiro five-membered rings, respectively [25][26]. Strepsesquitriol bearing bridged five-membered rings was firstly synthesized by Li in 2024 [27]. The green fluorescent protein (GFP) core chromophore (o-LHBDI) displayed a potential application in organic light

C2 to C6 biobased carbonyl platforms for fine chemistry

• Jingjing Jiang,
• Muhammad Noman Haider Tariq,
• Florence Popowycz,
• Yanlong Gu and
• Yves Queneau

Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165

• temperatures between 180–240 ºC in a maximum yield of about 30–40% (Scheme 14) [72][73]. Dihydroxyacetone (DHA) The formose process is the conversion of formaldehyde to glycolaldehyde and 1,3-dihydroxy-2-propanone (dihydroxyacetone, DHA). A computational protein-directed evolution allowed to create "formolase

Rhodium-catalysed connective synthesis of diverse reactive probes bearing S(VI) electrophilic warheads

• Scott Rice,
• Julian Chesti,
• William R. T. Mosedale,
• Megan H. Wright,
• Stephen P. Marsden,
• Terry K. Smith and
• Adam Nelson

Beilstein J. Org. Chem. 2025, 21, 1924–1931, doi:10.3762/bjoc.21.150

• the discovery of small molecule modifiers for investigating and engineering proteins. Keywords: covalent probes; molecular diversity; rhodium carbenoids; Introduction Diverse sets of reactive probes can facilitate the discovery of chemical tools and drugs that chemically modify protein targets [1][2

Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs

• Almaz A. Zagidullin,
• Emil R. Bulatov,
• Mikhail N. Khrizanforov,
• Damir R. Davletshin,
• Elvina M. Gilyazova,
• Ivan A. Strelkov and
• Vasily A. Miluykov

Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148

• interactions. The method provides insight into protein structures and functions using electrochemical methods that can also be applied to studies involving alkylating agents [25][26]. In this study, LSV was employed to investigate the interactions between human serum albumin (HSA) and the three prospective

• albumin was chosen as a model protein because of its well‐characterized structure and the presence of reactive sites that are known to be susceptible to alkylation. In standard aqueous media, the electrochemical oxidation of HSA can be observed via LSV as a broad wave, which is often attributed to the

• oxidation of amide and other amino acid side‐chain fragments. By tracking changes in this oxidation signal upon addition of an alkylating agent, we can infer whether the agent has effectively reacted with (and thus structurally altered) the protein. As illustrated by the black trace in the LSV plot, pure

Photoswitches beyond azobenzene: a beginner’s guide

• Michela Marcon,
• Christoph Haag and
• Burkhard König

Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143

• the protein-binding site than the bent Z-isomer. However, it would be more desirable to have an inactive molecule in its most stable state which can be activated by irradiation [51][59]. Hernando and co-workers were able to design photoswitchable neurotransmitters of ionotropic kainate receptors by

4-(1-Methylamino)ethylidene-1,5-disubstituted pyrrolidine-2,3-diones: synthesis, anti-inflammatory effect and in silico approaches

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Luc Van Meervelt,
• Do Thi Thao and
• Nguyen Minh Thong

Beilstein J. Org. Chem. 2025, 21, 817–829, doi:10.3762/bjoc.21.65

• and protein which enhance the stability of the complex [37][38]. The molecular docking study evaluated the binding affinities of potential drug candidates (iNOS–5a, 5b, 5c, 5d, 5e) and the reference compound (iNOS–DEX) with the inducible nitric oxide synthase (iNOS) enzyme (Figure 4 and Figure 5). The

• , Trp194, Gly202, Pro350, Phe369, and Tyr489, further contributing to the stabilization of the ligand–protein complexes. More importantly, the occurrence of an electron-withdrawing group, nitro group (NO2), on the aromatic ring linked to the 1-position of the pyrrolidine-2,3-dione core may help compound 5e

• stabilized the ligand–protein complexes. Experimental evaluations have confirmed these findings in which compound 5e demonstrated the most potent inhibitory activity against iNOS, achieving an IC50 value of 43.69 ± 5.26 µM substantially lower than that of 5a (IC50 = 78.65 ± 6.88 µM) and 5b (IC50 = 95.66

Orthogonal photoswitching of heterobivalent azobenzene glycoclusters: the effect of glycoligand orientation in bacterial adhesion

• Leon M. Friedrich and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2025, 21, 736–748, doi:10.3762/bjoc.21.57

• the structural determinants of the recognition process is a prerequisite for understanding and manipulating carbohydrate–protein interactions, such as in the inhibition of carbohydrate-specific bacterial adhesion. For receptor binding, glycoligands have to be properly oriented in three-dimensional

• ; Introduction Carbohydrate–protein interactions are fundamental in cell biology, such as in cell–cell interactions, immune cell trafficking or bacterial adhesion, and therefore carbohydrate recognition is subject of intensive research. In particular, a plethora of synthetic glycoconjugates have been designed

• diverse interactions with primary and secondary carbohydrate binding sites of the protein [13]. For example, when an α-ᴅ-mannopyranosyl (Man) and a β-ᴅ-glucopyranosyl (Glc) unit were conjugated such that the relative orientation of the two sugar portions is varied – be it on enantiomeric or regioisomeric