Targeting the Pseudomonas quinolone signal quorum sensing system for the discovery of novel anti-infective pathoblockers

• Christian Schütz and
• Martin Empting

Beilstein J. Org. Chem. 2018, 14, 2627–2645, doi:10.3762/bjoc.14.241

• two metal atoms in the binuclear active center via a water molecule in contrast to 2-ABA, where the carboxylate occupies this position (Figure 12). Moreover both, 2-ABA and the ligands 24–26 are stabilized by hydrophobic interactions. Additionally, compounds 24 and 25 are interacting with a histidine

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• group report are scaffolds and moieties seen in typical medicinal chemistry syntheses. There are numerous examples of amino acid-derived substrates, either as the methoxybenzene electrophile (tyrosine type derivatives) or as the nucleophile (histidine and related structures such as the depicted triazole

Defining the hydrophobic interactions that drive competence stimulating peptide (CSP)-ComD binding in Streptococcus pneumoniae

• Bimal Koirala,
• Robert A. Hillman,
• Erin K. Tiwold,
• Michael A. Bertucci and
• Yftah Tal-Gan

Beilstein J. Org. Chem. 2018, 14, 1769–1777, doi:10.3762/bjoc.14.151

• threshold concentration, CSP binds and activates the transmembrane histidine kinase receptor ComD. Upon activation, ComD phosphorylates ComE. Phosphorylated ComE then autoactivates the competence QS circuit and upregulates the expression of genes involved in virulence factor production, biofilm formation

Two new 2-alkylquinolones, inhibitory to the fish skin ulcer pathogen Tenacibaculum maritimum, produced by a rhizobacterium of the genus Burkholderia sp.

• Dandan Li,
• Naoya Oku,
• Atsumi Hasada,
• Masafumi Shimizu and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2018, 14, 1446–1451, doi:10.3762/bjoc.14.122

• culture was inoculated into 100 mL of the IMM-HS production medium (glucose 1%, K2HPO4 0.36%, KH2PO4 0.41%, MgSO4·7H2O 0.02%, CaCl2·2H2O 0.01%, FeSO4·7H2O 0.002%, NH4Cl 0.1%, biotin 0.0001%, and L-histidine 0.4%), and shaken at 200 rpm at 30 °C for 4 days. For the extraction of secondary metabolites, 100

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

• rate. High buffer concentration has to be used and this makes elimination of salt and co-solute effects difficult. Since histidine residues are known to play a central role in the catalytic center of RNase A [58], one of the most extensively studied protein nucleases, catalysis by imidazole/imidazolium

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• green catalysis. Peptide dendrimers including aspartate, histidine and serine were utilized by Reymond et al. as catalytic esterase triad. Using fluorogenic 8-acyloxypyrene-1,3,6-trisulfonates as substrate (Figure 7) at the pH optimum of 5.5, triads’ activity was successfully demonstrated [107]. A

• noticeable rate enhancement was observed, related to a large apparent reactivity increase per catalytic site. Such an enhanced activity could be explained by the relatively high hydrophobic binding of the acyl group and the presence of histidine side chains that act as catalytic groups and as electrostatic

Position-dependent impact of hexafluoroleucine and trifluoroisoleucine on protease digestion

• Susanne Huhmann,
• Anne-Katrin Stegemann,
• Kristin Folmert,
• Damian Klemczak,
• Johann Moschner,
• Michelle Kube and
• Beate Koksch

Beilstein J. Org. Chem. 2017, 13, 2869–2882, doi:10.3762/bjoc.13.279

• phenylalanine, tyrosine, tryptophan, and leucine in the P1 position. Secondary hydrolysis also occurs at the carbonyl end of isoleucine, methionine, serine, threonine, valine, histidine, glycine, and alanine [47][58][59][60]. The S2 subsite of α-chymotrypsin generally prefers to accommodate hydrophobic residues

Synthesis of 1,3-cis-disubstituted sterically encumbered imidazolidinone organocatalysts

• Jan Wallbaum and
• Daniel B. Werz

Beilstein J. Org. Chem. 2017, 13, 2577–2583, doi:10.3762/bjoc.13.254

• in the reaction. The use of methyl-protected L-histidine-derived methyl amide 9a (Table 1, entry 1) gave the desired imidazolidinone 7b in 42% yield, whereas the unprotected derivative showed no conversion, probably because of its insolubility. The unprotected as well as the benzyl-protected L

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

• Matthias Wünsch,
• David Schröder,
• Tanja Fröhr,
• Lisa Teichmann,
• Sebastian Hedwig,
• Nils Janson,
• Clara Belu,
• Jasmin Simon,
• Shari Heidemeyer,
• Philipp Holtkamp,
• Jens Rudlof,
• Lennard Klemme,
• Alessa Hinzmann,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2017, 13, 2428–2441, doi:10.3762/bjoc.13.240

• % [21]. Synthesis of propargylamines containing electron-withdrawing substituents Aromatic and carbonyl substituents in the Cβ-position of propargylamines (occurring in analogoues of the amino acids phenylalanine, tyrosine, histidine, tryptophan, aspartic acid and asparagine) increase the acidity of the

• imine 5h) after desilylation with TBAF (Table 2). As the benzylic proton of sulfinylimine 5h is quite acidic, approach II was not pursued for the synthesis of propargylamines analogous to tyrosine, histidine, tryptophan, and aspartate. Proteinogenic amino acids do not contain substituents, which

Sulfation and amidinohydrolysis in the biosynthesis of giant linear polyenes

• Hui Hong,
• Markiyan Samborskyy,
• Katsiaryna Usachova,
• Katharina Schnatz and
• Peter F. Leadlay

Beilstein J. Org. Chem. 2017, 13, 2408–2415, doi:10.3762/bjoc.13.238

• Medi0234 (41% identity, 57% similarity). Each of these three genes was cloned and expressed in Escherichia coli as an N-terminally histidine-tagged protein as described in the Experimental section, and purified by chromatography on a Ni-NTA column. The putative amidinohydrolases Medi2865 and Medi0234 were

Conformational study of L-methionine and L-cysteine derivatives through quantum chemical calculations and ³J_HH coupling constant analyses

• Weslley G. D. P. Silva,
• Carolyne B. Braga and
• Roberto Rittner

Beilstein J. Org. Chem. 2017, 13, 925–937, doi:10.3762/bjoc.13.94

• derivatives of tryptophan [20], phenylalanine and tyrosine [21], aspartic acid [22], proline [23] and histidine [24]. These studies have provided significant results to understand the importance of the corresponding amino acids in processes in which they take part in the polypeptide chain. Furthermore, these

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• -octadecene) that could subsequently be functionalised with hydrophilic PEG-diamine, providing an amine functionality for conjugation with glucosamine, histidine, arginine and folate. The yellow/red emissive loaded-CDs were shown to be viable bioimaging probes in live cells, since their emission did not

Polyketide stereocontrol: a study in chemical biology

• Kira J. Weissman

Beilstein J. Org. Chem. 2017, 13, 348–371, doi:10.3762/bjoc.13.39

• on this class of enzymes suggest a catalytic mechanism in which a single histidine plays the role of both general acid and base [97][98][99]. Extending this proposal to PKS DHs which operate on C-2 methylated intermediates, implies that only D-methylated ((2R), unepimerized) compounds will be

Posttranslational isoprenylation of tryptophan in bacteria

• Masahiro Okada,
• Tomotoshi Sugita and
• Ikuro Abe

Beilstein J. Org. Chem. 2017, 13, 338–346, doi:10.3762/bjoc.13.37

• isoprenyltransferase for the ComX peptide, which is encoded next in the cluster [35]. The downstream ComP is homologous to transmembrane histidine kinase, and ComA is homologous to a response regulator [36]. Therefore, the two proteins constitute the large family of two-component regulatory systems widely found in

Enduracididine, a rare amino acid component of peptide antibiotics: Natural products and synthesis

• Darcy J. Atkinson,
• Briar J. Naysmith,
• Daniel P. Furkert and
• Margaret A. Brimble

Beilstein J. Org. Chem. 2016, 12, 2325–2342, doi:10.3762/bjoc.12.226

• of enduracididine In 1984, a radio-labelling study was carried out to determine the biosynthesis of enduracididine (1) [48]. Arginine (18) and its precursors ornithine and citrulline, were found to be incorporated into enduracididine (1), but not histidine (19) [48]. Between the enduracidin and

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• to a histidine or an asparagine residue in their active site. This exchange avoids the dehydration reaction and might facilitate the activation of the hydroxy group for nucleophilic attack on the Michael system by proton abstraction. PS domains also form a distinct phylogenetic clade compared to DH

Mutagenic activity of quaternary ammonium salt derivatives of carbohydrates

• Barbara Dmochowska,
• Karol Sikora,
• Anna Woziwodzka,
• Jacek Piosik and
• Beata Podgórska

Beilstein J. Org. Chem. 2016, 12, 1434–1439, doi:10.3762/bjoc.12.138

• positive control (C2) was considered 100%. Mutagenic activity of the QASs in the Ames test with histidine-dependent Salmonella typhimurium TA98 strain. A, 4a; B, 4b; C, 5a; D, 5b; E, 6a; F, 6b; G, 7a; H, 7b. C1 (marked in white), negative (water) control; C2 (marked in black), positive control (2-amino-3

Biosynthesis of α-pyrones

• Till F. Schäberle

Beilstein J. Org. Chem. 2016, 12, 571–588, doi:10.3762/bjoc.12.56

• the catalytic cysteine residue. Subsequently, the thioester bond is cleaved by the nucleophilic water molecule, which itself is activated through hydrogen bonding to the catalytic cysteine and a histidine residue. Thereby, the β-keto acid intermediate is generated. This intermediate is proposed to be

• molecule, yielding the csypyrones harboring four O-atoms. The first step of the proposed mechanism was delignated from a set of in vitro assays, which indicated that the 18O atom of the H218O molecule – which should be activated by hydrogen bonds networks with a histidine and the catalytic cysteine residue

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

• Eric V. Anslyn

Beilstein J. Org. Chem. 2016, 12, 362–376, doi:10.3762/bjoc.12.40

• our group are on wines. As with our earlier work, the approach uses a suite of combinatorial peptides as differential receptors. The peptides are biased with a large fraction of the amino acid histidine, are metallated with Cu, Ni, and Zn, and bind indicators to create a series of IDAs that can

Supramolecular structures based on regioisomers of cinnamyl-α-cyclodextrins – new media for capillary separation techniques

• Gabor Benkovics,
• Ondrej Hodek,
• Martina Havlikova,
• Zuzana Bosakova,
• Pavel Coufal,
• Milo Malanga,
• Eva Fenyvesi,
• Andras Darcsi,
• Szabolcs Beni and
• Jindrich Jindrich

Beilstein J. Org. Chem. 2016, 12, 97–109, doi:10.3762/bjoc.12.11

• capillary electrophoresis. The influence of the addition of 2-O-Cin-α-CD and 3-O-Cin-α-CD to the background electrolyte (BGE) and its impact on the effective mobilities of eighteen selected analytes were tested. Nine analytes were in the form of cations (aniline, antipyrine, L-histidine, DL-tyrosine, DL

Bromotyrosine-derived alkaloids from the Caribbean sponge Aplysina lacunosa

• Qun Göthel,
• Thanchanok Sirirak and
• Matthias Köck

Beilstein J. Org. Chem. 2015, 11, 2334–2342, doi:10.3762/bjoc.11.254

• activities, including antiviral [2], antibiotic [3][4][5], Na+/K+ ATPase inhibition [6][7][8], anti-HIV [9][10], antifungal [11], histidine-H3 antagonist [12], cytotoxic [13][14], and antimalarial activities [15][16][17]. During our investigation of the chemical constituents of Aplysina lacunosa (Aplysinidae

Active site diversification of P450cam with indole generates catalysts for benzylic oxidation reactions

• Paul P. Kelly,
• Anja Eichler,
• Susanne Herter,
• David C. Kranz,
• Nicholas J. Turner and
• Sabine L. Flitsch

Beilstein J. Org. Chem. 2015, 11, 1713–1720, doi:10.3762/bjoc.11.186

• histidine were not among the active site residues of the parent (or wild type) enzyme but appeared in several of the new variants, thus introducing a thiol, polar or basic group where previously none existed. More bulky aromatic side chains in libraries I and II were often substituted for smaller side

Multivalency as a chemical organization and action principle

• Rainer Haag

Beilstein J. Org. Chem. 2015, 11, 848–849, doi:10.3762/bjoc.11.94

• ], peptide–polymer interactions [17][18][19][20] tripodal-catecholates [21] and polycatechol–surface interactions [22] as well as multivalent organocatalyts [23]. Finally, multivalent dendritic poly(arginine/histidine)-siRNA complexes are evaluated regarding their transfection efficiency [24]. In the future

Multivalent dendritic polyglycerolamine with arginine and histidine end groups for efficient siRNA transfection

• Fatemeh Sheikhi Mehrabadi,
• Hanxiang Zeng,
• Mark Johnson,
• Cathleen Schlesener,
• Zhibin Guan and
• Rainer Haag

Beilstein J. Org. Chem. 2015, 11, 763–772, doi:10.3762/bjoc.11.86

• , arginine (Arg) and histidine (His). To investigate the effects from introducing Arg and His to dPG, the resulting polyplexes of amino acid functionalized dPG-NH2s (AAdPGs)/siRNA were evaluated regarding cytotoxicity, transfection efficiency, and cellular uptake. Among AAdPGs, an optimal vector with (1:3

• residues (His) are important for safe and efficient siRNA transfection, this study indicates that AAdPGs containing higher degrees of His display lower cytotoxicity and more efficient endosomal escape. Keywords: arginine; dendritic polyglycerolamine; histidine; multivalent vector; siRNA delivery

• biomedical purposes [6] such as anti-inflammatory [10] and anticancer therapy [11][12]. Previously a number of cationic polymers like chitosan [13][14][15], PEI [16], and PAMAM [17] have been post-modified with histidine (His) or arginine (Arg) groups. The introduction of histidine groups has been beneficial

Articulated rods – a novel class of molecular rods based on oligospiroketals (OSK)

• Pablo Wessig,
• Roswitha Merkel and
• Peter Müller

Beilstein J. Org. Chem. 2015, 11, 74–84, doi:10.3762/bjoc.11.11

• aim we chose metal cations as triggers and imidazole moieties as chelating groups at the ARs. The chelating event should be monitored by the influence on the [4 + 4] cycloaddition of anthracene. The synthesis of such a fourfold functionalized AR is based on the natural amino acid L-histidine. In the

• first step histidine methylester hydrochloride (40) is acylated with anthracene-9-acetic acid to give 41. After saponification of the ester the potassium salt of the corresponding acid 42 was treated with 32c affording the articulated rod 43 in quantitative yield (Scheme 10). The stretched–folded