New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• transporters to form the siderophore Fe(III) complex extracellularly [2][3]. Subsequently, the stable and water soluble siderophore Fe(III) complex is transported across the cell membrane into the cytoplasm, where the iron is released from the complex by reduction, generating free Fe(II) ions that are

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• into the cell through membrane receptors and transporters. Eventually, the bound metal is released through reductive or hydrolytic mechanisms [2]. In the past years, β-proteobacteria have received increasing attention as producers of siderophores with interesting chemical features. For instance

Navigating and expanding the roadmap of natural product genome mining tools

• Friederike Biermann,
• Sebastian L. Wenski and
• Eric J. N. Helfrich

Beilstein J. Org. Chem. 2022, 18, 1656–1671, doi:10.3762/bjoc.18.178

• gene sets) are difficult to identify. The enzymes encoded in core biosynthetic genes are responsible for assembling the NP backbone; additional biosynthetic genes encode tailoring enzymes and other components of a pathway (transporters, regulators, immunity enzymes). Conserved domains are depicted in

Amamistatins isolated from Nocardia altamirensis

• Till Steinmetz,
• Wolf Hiller and
• Markus Nett

Beilstein J. Org. Chem. 2022, 18, 360–367, doi:10.3762/bjoc.18.40

• featuring ligand groups with nitrogen or sulfur as donor atoms [4]. The siderophore–iron complexes are recognized by highly selective microbial transporters. Following their translocation into the cell, the bound iron is released via a reductive or hydrolytic mechanism [2] Members of the genus Nocardia are

A systems-based framework to computationally describe putative transcription factors and signaling pathways regulating glycan biosynthesis

• Theodore Groth,
• Rudiyanto Gunawan and
• Sriram Neelamegham

Beilstein J. Org. Chem. 2021, 17, 1712–1724, doi:10.3762/bjoc.17.119

• termed glycogenes [1][2]. These glycogenes include the glycosyltransferases, glycosidases, sulfotransferases, transporters, etc. The expression of these glycogenes is in turn driven by the action of a class of proteins called transcription factors (TFs). These TFs regulate gene expression by binding

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• heating for the synthesis of a series of alkyl- and arylbiguanides to study the drug uptake of biguanide derivatives by organic cation transporters OCT1 and OCT2. The reaction conditions involved refluxing acetonitrile overnight with 1.5 equivalents of TMSCl, resulting in the desired products in variable

Biochemistry of fluoroprolines: the prospect of making fluorine a bioelement

• Vladimir Kubyshkin,
• Rebecca Davis and
• Nediljko Budisa

Beilstein J. Org. Chem. 2021, 17, 439–460, doi:10.3762/bjoc.17.40

• protein) and proW (encoding a permease) as well as proX (encoding a periplasmic protein) are located on the proU operon. The proline/betaine transporters accumulate proline and various other substrates inside the cells under high external salinity. They are tolerant to the transport of proline analogues

Automated high-content imaging for cellular uptake, from the Schmuck cation to the latest cyclic oligochalcogenides

• Rémi Martinent,
• Javier López-Andarias,
• Dimitri Moreau,
• Yangyang Cheng,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2020, 16, 2007–2016, doi:10.3762/bjoc.16.167

• unorthodox COC chemistry covering ETPs [52], diselenolanes [53], and benzopolysulfanes [54], the activity gradually increased. The Achilles heel of much research on new transporters for cellular uptake, from CPPs and Schmuck cations to CPDs and COCs, is the quantitative detection of the delivery in the

• employed to generate dose–response curves and to calculate the CP50 value of the transporters, described as the half-maximal cell penetration. In a CAPA, the final fluorescence response is usually recorded by flow cytometry [55][62]. In a HC CAPA, flow cytometry is replaced by HC automated microscopy

• thiols (left), preceding walking along the disulfide tracks, and micellar pores (right). CAPA assay for the complex 25, composed of three transporters 23 bound to one streptavidin 24 (with the structure of the homotetramer loaded with four biotins). Cytosolic delivery into HMG cells (a) has to precede

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• Financial support by the Swiss National Science Foundation (SNSF) is gratefully acknowledged: This research was funded by the Sinergia Project: Molecular identification of lipid transporters for protein glycosylation, Grant CRSII5_170923.

Sugar-derived oxazolone pseudotetrapeptide as γ-turn inducer and anion-selective transporter

• Sachin S. Burade,
• Sushil V. Pawar,
• Tanmoy Saha,
• Navanath Kumbhar,
• Amol S. Kotmale,
• Manzoor Ahmad,
• Pinaki Talukdar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2019, 15, 2419–2427, doi:10.3762/bjoc.15.234

• various diseases such as cystic fibrosis, Dent disease, Bartter syndrome, and epilepsy [34][35][36][37]. In order to mimic the regulatory functions in living systems, a wide range of anion transporters have been investigated that include peptides [38][39][40][41][42][43], oligoureas [44][45], anion-π

• slides [46][47], steroids [48][49], calixpyrroles [50][51], calixarenes [52][53], and other scaffolds [54][55][56]. In particular, peptide based transmembrane anion transporters have attracted great interest. For example, Ghadiri [38], Ranganathan [39], and Granja [40] have independently reported

• different types of cyclic peptides as anion transporters. Gale, Luis, and co-workers [41] have separately reported the linear pseudopeptides as receptors and transporters of chloride and nitrate anions. Inspired by our recent ion transport studies with fluorinated acyclic and cyclic sugar derived peptides

1,2,3-Triazolium macrocycles in supramolecular chemistry

• Mastaneh Safarnejad Shad,
• Pulikkal Veettil Santhini and
• Wim Dehaen

Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211

• critical role of negatively charged species in numerous biological, environmental, chemical and medicinal processes, anion receptors and transporters play an important role in supramolecular chemistry [17][29]. Thus, diverse anion receptors based on 1,2,3-triazolium recognition elements have been reported

Synthesis of nonracemic hydroxyglutamic acids

• Dorota G. Piotrowska,
• Iwona E. Głowacka,
• Andrzej E. Wróblewski and
• Liwia Lubowiecka

Beilstein J. Org. Chem. 2019, 15, 236–255, doi:10.3762/bjoc.15.22

• mGluR1 and as a weak antagonist of mGluR4 [18]. Excitatory amino acid transporters (EAAT) are effected by hydroxyglutamic acid in various degrees. For example, (2S,4S)-3 appeared to be a substrate at EAAT1-3, while (2S,4R)-3 did not interact with them [19][20]. A number of studies revealed that several

Olefin metathesis catalysts embedded in β-barrel proteins: creating artificial metalloproteins for olefin metathesis

• Daniel F. Sauer,
• Johannes Schiffels,
• Takashi Hayashi,
• Ulrich Schwaneberg and
• Jun Okuda

Beilstein J. Org. Chem. 2018, 14, 2861–2871, doi:10.3762/bjoc.14.265

• present as minor motifs or even dominate the overall protein structure [33][34]. Small β-barrels such as lipocalins (i.e., transporters of small hydrophobic molecules that play vital roles in many biological processes [35]) or heme-containing nitrophorins/nitrobindins of the all-β-barrel type (involved in

• point are relatively small and soluble proteins. As introduced vide supra, membrane-spanning porins and transporters of the all-β-barrel type, which are found in cellular outer membranes, constitute substantially larger “barrel” interiors and were thus utilized as scaffolds to house bulky GH-type

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• asymmetric catalysis and molecular recognition [5][6]. Besides, squaramides present a dual ability to recognize anions and cations through hydrogen bonding interactions, acting as ion sensors and transmembrane anion transporters [7]. This property has been crucial for the development of new drugs [8][9

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

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

• exploited for developing targeted cytotoxic agents: Dysregulation of translation initiation factors and regulators [14]. Mutations in epigenetic regulatory genes [15]. Overexpression of surface receptors like HER2R [16], folate receptor [17], GnRH receptor [18][19] and amino acid transporters [20

• transporters hENTs (human equilibrative nucleoside transporters) and hCNTs (human concentrative nucleoside transporters) and mostly through hENT1 (human equilibrative nucleoside transporter 1) [89][90]. After internalization, gemcitabine is sequentially mono-, di- and tri-phosphorylated by phosphorylating

Microfluidic radiosynthesis of [¹⁸F]FEMPT, a high affinity PET radiotracer for imaging serotonin receptors

• Thomas Lee Collier,
• Steven H. Liang,
• J. John Mann,
• Neil Vasdev and
• J. S. Dileep Kumar

Beilstein J. Org. Chem. 2017, 13, 2922–2927, doi:10.3762/bjoc.13.285

• supersensitivity. Significant research has been directed at the differences between agonist and antagonist binding to 5-HT1A receptors in Alzheimer's disease [10] and this interest has led to the development of a high-resolution in vivo atlas for four of the human brain's serotonin receptors and transporters [11

• -fluoroethane in the presence of K2CO3 (Scheme 1 and Supporting Information File 1). The in vitro binding assays to establish the potency and selectivity of FEMPT towards 5-HT1AR and various other biogenic amines, brain receptors, and transporters were evaluated by the National Institute of Mental Health

• Psychoactive Drug Screening Program (NIMH-PDSP). FEMPT shows 0.2 nM binding affinity (Ki) to 5-HT1AR. The next closest bindings for MPT are Sigma2 PC12, H1, 5-HT7, and 5-HT1B (Table 1) and are >50 times higher than 5-HT1AR. The Ki values for several other brain receptors and transporters were low (0.1 to 10 μM

Glycoscience@Synchrotron: Synchrotron radiation applied to structural glycoscience

• Serge Pérez and
• Daniele de Sanctis

Beilstein J. Org. Chem. 2017, 13, 1145–1167, doi:10.3762/bjoc.13.114

• hydrolases; glycosyl transferases; kinetic crystallography; lectins; polysaccharides; powder diffraction; small-angle X-ray scattering; starch; synchrotron radiation; transporters; X-ray crystallography; Introduction Over the last decade, glycoscience has greatly benefited from the development of structural

• modifications. Transporters and proteins purely involved in recognition (lectin, antibodies, carbohydrate binding modules, glycosaminoglycan binding proteins) are the other important classes of carbohydrate-binding proteins. Figure 7 shows the evolution of the number of carbohydrate interacting proteins that

• thrombin and antithrombin at 2.5 Å resolution. For the time being, this is one of the largest oligosaccharide structures ever established throughout macromolecular X-ray crystallography (Figure 12) [59]. Transporters: Soluble sugars serve many purposes in complex organisms. Their cellular exchange relies

Expression, purification and structural analysis of functional GABA transporter 1 using the baculovirus expression system

• Jing Hu,
• Chris Weise,
• Christoph Böttcher,
• Hua Fan and
• Jian Yin

Beilstein J. Org. Chem. 2017, 13, 874–882, doi:10.3762/bjoc.13.88

• neurotransmission is efficiently terminated through the quick removal of GABA from the synaptic cleft by GABA transporters (GATs). The activities of GATs are important for controlling the concentration and dwell time of GABA in the synaptic cleft and tightly regulating the synaptic inhibition of the GABA receptor

• [1]. GATs, which are located in the plasma membranes of neurons and glia cells, belong to the solute carrier 6 (SLC6) family in mammals, which is subdivided into four groups based on sequence composition: GATs, GABA, osmolyte and creatine transporters, neurotransmitter amino acid, monoamine and

• nutrient amino acid/orphan transporters [2][3]. Four subtypes of GATs (GAT1–4) have been identified thus far [4]. GAT1, the first neurotransmitter transporter to be cloned, is abundantly but restrictively expressed throughout rat, mouse, and human CNSs [4][5][6][7][8]. The transmembrane (TM) topology of

Opportunities and challenges for the sustainable production of structurally complex diterpenoids in recombinant microbial systems

• Katarina Kemper,
• Max Hirte,
• Markus Reinbold,
• Monika Fuchs and
• Thomas Brück

Beilstein J. Org. Chem. 2017, 13, 845–854, doi:10.3762/bjoc.13.85

• transporters to enhance extracellular product secretion can be a viable support for this apolar-phase-capture [96]. However, these methods are no longer applicable as soon as further engineering steps involve polarization of the product backbone. A summary of the various areas that have to be covered for

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

• transporters (ABCA1, ABCG1, and SR-BI) involved in this process could be very useful in the fight against atherosclerosis pathogenesis. As pointed out by Coisne and co-workers, “RCT alterations have been poorly studied at the arterial endothelial cell and smooth muscle cells levels” [132]. Consequently, the

• interaction. Consequently, the cellular cholesterol involved in atherosclerotic lesions is lowered and the expression of ABCA1 and ABCG1 transporters involved in RCT is clearly modulated. In 2016, Zimmer et al. published on the effect of HP-β-CD in order to reduce atherosclerotic plaques [133]. The HP-β-CD

Smart molecules for imaging, sensing and health (SMITH)

• Bradley D. Smith

Beilstein J. Org. Chem. 2015, 11, 2540–2548, doi:10.3762/bjoc.11.274

• , and I apologize for any distortion of credit. To assist the interested reader, each research topic includes references to relevant review articles by leading groups in the field. Membrane transport Molecular transporters that alter the concentration gradients of anions and biomolecules across a cell

• develop a series of mobile carriers for chloride ions across liposome and cell membranes [6]. There continues to be a strong community interest in chloride transporters as they are expected to exhibit interesting biological activity [7]. In addition, my group developed some of the first synthetic

• author as director of the Notre Dame Integrated Imaging Facility. Chronological progression of Smith group research projects. Molecular transporters promote translocation of ions or hydrophilic biomolecules across a synthetic or biological membrane. Macrocyclic receptor that binds solvent separated ion

Preparation and evaluation of cyclodextrin polypseudorotaxane with PEGylated liposome as a sustained release drug carrier

• Kayoko Hayashida,
• Taishi Higashi,
• Daichi Kono,
• Keiichi Motoyama,
• Koki Wada and
• Hidetoshi Arima

Beilstein J. Org. Chem. 2014, 10, 2756–2764, doi:10.3762/bjoc.10.292

• , phospholipids and proteins of biological membranes in the higher concentration range. Thus, CDs are utilized for studying the functions of caveolae, lipid rafts, and cholesterol transporters in various fields of cell biology [5]. Interestingly, CDs can also form inclusion complexes with linear polymers. Harada

Staudinger ligation towards cyclodextrin dimers in aqueous/organic media. Synthesis, conformations and guest-encapsulation ability

• Malamatenia D. Manouilidou,
• Yannis G. Lazarou,
• Irene M. Mavridis and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 774–783, doi:10.3762/bjoc.10.73

• and animals in vivo have been demonstrated [6]. Cyclodextrins (CDs, Scheme 1c), are cyclic oligomers of glucopyranose that act as hosts to hydrophobic molecules in aqueous environment [9][10]. CDs have been recognized as potent drug solubilizers and transporters through biological barriers with

New hydrogen-bonding organocatalysts: Chiral cyclophosphazanes and phosphorus amides as catalysts for asymmetric Michael additions

• Helge Klare,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2014, 10, 224–236, doi:10.3762/bjoc.10.18

• reaction of methyl acrylate with benzaldehyde the substituted triamide catalysts show a comparable or an even superior activity relative to the thiourea analogue. Recently, Gale et al. demonstrated that the same phosphoric triamides effectively act as anion transporters by hydrogen bonding [19]. These