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Search for "threonine" in Full Text gives 70 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis of ether lipids: natural compounds and analogues
Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96
Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition
Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143
- . Common structural motifs include a polyunsaturated acyclic chain with an unsaturated lactone ring and an amine-containing side chain (Figure 1). These natural products have attracted much attention due to their original structure and to their activity as inhibitors of the serine/threonine phosphatase
Synthesis of tryptophan-dehydrobutyrine diketopiperazine and biological activity of hangtaimycin and its co-metabolites
Beilstein J. Org. Chem. 2022, 18, 1159–1165, doi:10.3762/bjoc.18.120
- -butyloxycarbonyl (Boc)-protected threonine using bis(2-oxo-3-oxazolidinyl)phosphinic chloride (BOP-Cl) [14][15] and Hünig’s base to give 9. Cleavage of the Boc group with 5% TFA followed by basic treatment resulted in the cyclisation to the dioxopiperazine 10. Acetylation and subsequent treatment with LiClO4 and
- DBU is a common strategy for the dehydration of serine and threonine units in peptides [16], but unfortunately the acetylation of 10 failed. Interestingly, the direct treatment of 10 with LiClO4 and DBU under prolonged reaction times (3 days) resulted in the elimination of water. This reaction
- step using milder conditions (Scheme 3). The newly developed synthesis started from 7 that was Boc-protected at the indole to yield 11. Removal of the benzyl group by catalytic hydrogenation to 12 was followed by coupling with benzyloxycarbonyl (Cbz) and methoxymethyl (MOM)-protected threonine to give
Amamistatins isolated from Nocardia altamirensis
Beilstein J. Org. Chem. 2022, 18, 360–367, doi:10.3762/bjoc.18.40
- help of COSY and HMBC data two residues were identified, including a threonine and a salicylic acid moiety. The two partial structures can be connected via an ester bond due to a key HMBC correlation from H-3 to C-5. To analyze the configuration of the isolated compounds, their optical rotations were
- reductive degradation of amamistatin-type siderophores. Compound 6 represents a possible shunt product of amamistatin biosynthesis. A similar molecule and its putative biosynthetic pathway were recently described by Jaspars et al. [12]. In accordance with this proposal, salicylic acid and ʟ-threonine would
Isolation and characterization of new phenolic siderophores with antimicrobial properties from Pseudomonas sp. UIAU-6B
Beilstein J. Org. Chem. 2021, 17, 2390–2398, doi:10.3762/bjoc.17.156
- analyses. The absolute configuration of the threonine residue in compounds 1–5 was determined by Marfey analysis. The antimicrobial evaluation of compound 4 exhibited the most potent activity against vancomycin-sensitive Enterococcus faecium VS144754, followed by 3 and 5, with MIC values ranging from 8 to
- acid unit, confirmed by long-range correlations observed in the HMBC spectrum from H-2, H-4 to C-6 (δC 113.2), and H-5 to the quaternary carbon C-7 (δC 170.0). On the other hand, the COSY spectrum confirmed the presence of a CH3–CH–CH spin system (H3-12, H-11, and H-9) reminiscent of a threonine unit
- unsaturation. The detailed analysis of 1H and 2D NMR spectra (see Table 1 and Supporting Information File 1) suggested the presence of both, the salicylic acid (H-2/H-3/H-4/H-5) and the linear threonine subunits found in 1, which were supported by the HMBC correlations shown in Figure 2. The major difference
A systems-based framework to computationally describe putative transcription factors and signaling pathways regulating glycan biosynthesis
Beilstein J. Org. Chem. 2021, 17, 1712–1724, doi:10.3762/bjoc.17.119
- -value = 0.035). SMAD proteins are activated by TGF-β signaling and bind to DNA to act as cofactors to recruit TFs. SMAD2 has been shown to act as a tumor metastasis suppressor in cell lines [32][33]. This TF was found to regulate GALNT1 (ρ = 0.54, RP = 1.00), which adds GalNAc to serine or threonine
- the addition of GlcNAc to processed N-linked glycan structures. These include all the MGAT enzymes. 7) GalNAc-type O-glycans: O-linked glycans are attached to serine (Ser) or threonine (Thr) on peptides, where GalNAc is the root carbohydrate. This is mediated by a family of about 20 Golgi-resident
Synthesis of legonmycins A and B, C(7a)-hydroxylated bacterial pyrrolizidines
Beilstein J. Org. Chem. 2021, 17, 334–342, doi:10.3762/bjoc.17.31
- ]. Proteins coded by three of these genes (LgnA, LgnB, and LgnD) were shown to assemble legonindolizidines A (1) and B (2) – from proline, threonine, and a fatty acid component – which are then converted by LgnC, a flavin-dependent monooxygenase, into the corresponding legonmycins (3 and 4) via a sequence of
- described in this paper, concise syntheses of the legonmycins. Results and Discussion The legonmycins are unique among the bacterial pyrrolizidines in bearing a C(2) methyl group. The biosynthetic study [22] demonstrates that this methyl group originates from the terminal carbon in threonine and not, as
Molecular basis for protein–protein interactions
Beilstein J. Org. Chem. 2021, 17, 1–10, doi:10.3762/bjoc.17.1
- interactions but have a high propensity to form interprotein interactions. In contrast, serine, threonine, asparagine (polar uncharged), alanine, valine, isoleucine (hydrophobic), cysteine, proline, and glycine are less likely to form interprotein interactions and bifurcated interactions. The binding mode in
A consensus-based and readable extension of Linear Code for Reaction Rules (LiCoRR)
Beilstein J. Org. Chem. 2020, 16, 2645–2662, doi:10.3762/bjoc.16.215
- be reserved for other future uses. To specify a glycopeptide, users may also inscribe them directly in the peptide using the existing branching rules: “PEP(AG(LY)CAN)TIDE” would describe a biantennary glycan bound to the threonine of a peptide. Because the number sign is used to indicate a
- rule can be extended to glycopeptides providing a means of representing glycans directly embedded in a glycopeptide. “PEP(Gal[3S]b3(GNb6)AN)TIDE” would describe a trisaccharide O-glycan bound to the threonine of an eponymously named glycoprotein. Overall, the consensus in these representations centers
Comparative ligand structural analytics illustrated on variably glycosylated MUC1 antigen–antibody binding
Beilstein J. Org. Chem. 2020, 16, 2540–2550, doi:10.3762/bjoc.16.206
- structures, but otherwise, the end-to-end distance is very similar for both bound antigens. Ramachandran analysis The φ–ψ angles of the antigens are considered using a Ramachandran plot. Figure 4 shows a Ramachandran plot for two key amino acids, the glycosylated threonine (Thr4) and neighboring aspartate
- the φ–ψ angles for amino acid 4 of the peptide, threonine. The left panel of Ramachandran plots are for the antigen, and the right panel are for the Tn-antigen. The first two rows are for the antigens in solution (unbound, A–H), while the final two rows are for the antigens bound to the antibody (I–P
Syntheses of spliceostatins and thailanstatins: a review
Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166
- Syntheses from ʟ-threonine-derived aldehyde Three groups utilized 4-formyl-2,2,5-trimethyl-3-oxazolidine (24) [21], derived from relatively inexpensive ʟ-threonine (<$1/g in bulk) as a chiral pool precursor for the amine stereocenter of the (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran fragment. In
Fabclavine diversity in Xenorhabdus bacteria
Beilstein J. Org. Chem. 2020, 16, 956–965, doi:10.3762/bjoc.16.84
- (Ala) and the sixth position (R2/R3) between proline (Pro), valine (Val) and threonine (Thr). The polyamine can differ in the length from three to five amine units (m) and is connected via one to three partially reduced polyketide C2 units (n) with the NRPS part. In this work, 22 yet unknown
A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions
Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52
Synthesis and conformational preferences of short analogues of antifreeze glycopeptides (AFGP)
Beilstein J. Org. Chem. 2019, 15, 1581–1591, doi:10.3762/bjoc.15.162
- of repeating tripeptide unit (-Ala-Ala-Thr*-), glycosylated at the threonine side chain. However, on the microscopic level, the mechanism of action of these compounds remains unclear. As previous research has shown, antifreeze activity of antifreeze glycopeptides strongly relies on the overall
- each hydroxy group in the threonine side chain is glycosylated with the disaccharide β-ᴅ-galactosyl-(1→3)-α-N-acetyl-ᴅ-galactosamine [4]. Even though the macroscopic properties of AFGPs, such as thermal hysteresis [5][6] and ice recrystallization inhibition [7][8][9] have been well described, the
- 2-acetamido-2-deoxy-ᴅ-galactopyranosyl residue (ᴅ-GalNAc) attached to an allo-threonine-containing PP II helical peptide or containing ᴅ-GalNAc attached to a fully ᴅ-configured PP II helical peptide (retro-inverso) are inactive, while the corresponding ʟ-configured peptide showed antifreeze activity
Synthesis of the polyketide section of seragamide A and related cyclodepsipeptides via Negishi cross coupling
Beilstein J. Org. Chem. 2019, 15, 577–583, doi:10.3762/bjoc.15.53
- of 21%. It proved to be possible to liberate the free 8-hydroxynonenoic acid and to couple it with a protected tripeptide composed of L-alanine, N,O-dimethyl-D-iodotyrosine, and TIPS-protected L-threonine, which occurs as partial structure of seragamide A. The tripeptide section of seragamide A was
- Suberites japonicus (Thiele) has been synthesized only once, with relay ring-closing metathesis being the key step [9]. Characteristically, seragamides A–E exhibit a L-threonine unit at the C-terminus of the peptide moiety. There is a considerable body of work on the synthesis of the C12 polyketide section
- satisfying. After Boc removal at 22, HATU/HOAt-mediated coupling with Boc-protected L-alanine afforded dipeptide 26, which was saponified and coupled with TIPS-protected threonine methyl ester (obtained with TIPSCl/DBU/MeCN) to provide tripeptide 27 (Scheme 5). Peptides 26 and 27 were obtained in nearly
Chemical structure of cichorinotoxin, a cyclic lipodepsipeptide that is produced by Pseudomonas cichorii and causes varnish spots on lettuce
Beilstein J. Org. Chem. 2019, 15, 299–309, doi:10.3762/bjoc.15.27
- obtained under controlled reaction conditions, clearly indicated that one amino group (Dab) and three OH groups are present in the toxin. As shown in Table 1, cichorinotoxin has three OH groups in its structure due to the presence of two serine residues and one threonine residue. In addition, one 3
Lectins of Mycobacterium tuberculosis – rarely studied proteins
Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1
- modifications of glycocalyx proteins are N-glycans (asparagine-linked) and O-glycans (serine- or threonine-linked), while glycosphingolipids are the major subclass of glycosylated lipids in the cell membrane of human cells (Figure 2). While many core elements of glycocalyx oligosaccharides are conserved between
Artificial bioconjugates with naturally occurring linkages: the use of phosphodiester
Beilstein J. Org. Chem. 2018, 14, 1946–1955, doi:10.3762/bjoc.14.169
- compatibility is of immense versatility since synthesized peptide fragments, which are cleaved from their supports thus freeing the C-terminus, could directly be conjugated to the 5’-terminus of oligonucleotides via tyrosine, serine, or threonine side chains. In order to demonstrate such a versatile conjugation
Diazirine-functionalized mannosides for photoaffinity labeling: trouble with FimH
Beilstein J. Org. Chem. 2018, 14, 1890–1900, doi:10.3762/bjoc.14.163
- arbitrarily as we have frequently employed them to optimize mass spectrometric procedures. Also, we were interested to test, if threonine or tyrosine residues, respectively, would lead to better labeling efficiency. Because mannoside 3 is poorly water soluble, it was dissolved in methanol and then added to
Glycosylation reactions mediated by hypervalent iodine: application to the synthesis of nucleosides and carbohydrates
Beilstein J. Org. Chem. 2018, 14, 1595–1618, doi:10.3762/bjoc.14.137
- several experiments, treatment with a catalytic amount of TMSOTf was found to be suitable for the intramolecular glycosylation, giving the corresponding acid, which was easily converted to the corresponding methyl ester 180 under EDCI/DMAP/MeOH conditions [85]. Similarly, the reaction of the threonine
Recyclable hypervalent-iodine-mediated solid-phase peptide synthesis and cyclic peptide synthesis
Beilstein J. Org. Chem. 2018, 14, 1112–1119, doi:10.3762/bjoc.14.97
- ]. Compared with classical solution-phase peptide synthesis, the fast development of SPPS is mainly due to its short reaction time, high efficiency, low racemization, simple work-up and automation. In recent decades, various strategies, for example, native chemical ligation (NCL) [32] and serine/threonine
- moderate yield (Table 1, entries 3 and 4). Notably, it is unnecessary to protect the hydroxy group of serine, threonine, or tyrosine in advance in the synthesis of these four peptides. The presence of an unprotected hydroxy group does not affect the coupling efficiency, which is consistent with peptide
A stereoselective and flexible synthesis to access both enantiomers of N-acetylgalactosamine and peracetylated N-acetylidosamine
Beilstein J. Org. Chem. 2018, 14, 856–860, doi:10.3762/bjoc.14.71
- , glycoproteins serve as ligands for specific extracellular recognition processes toward, e.g., enzymes, lectins or antibodies [2]. In O-linked glycoproteins, also known as mucins, GalNAc becomes covalently α-linked to serine or threonine during post-translational modifications [3][4][5]. This glycoconjugate
Carbohydrate inhibitors of cholera toxin
Beilstein J. Org. Chem. 2018, 14, 484–498, doi:10.3762/bjoc.14.34
- a non-binding mutant of the target CTB protein [66], oxidised the N-terminal threonine residue of each subunit to an aldehyde and then chemically attached GM1os ligands by oxime ligation (Figure 15). This neoglycoprotein was able to display the five copies of the carbohydrate ligand with appropriate
Position-dependent impact of hexafluoroleucine and trifluoroisoleucine on protease digestion
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
The use of 4,4,4-trifluorothreonine to stabilize extended peptide structures and mimic β-strands
Beilstein J. Org. Chem. 2017, 13, 2842–2853, doi:10.3762/bjoc.13.276
- , L-threonine, (2S,3R)-L-CF3-threonine and (2S,3S)-L-CF3-threonine were prepared. The capacity of (2S,3S)- and (2S,3R)-CF3-threonine analogues to stabilize an extended structure when introduced in the central position of pentapeptides is demonstrated by NMR conformational studies and molecular
- dynamics simulations. CF3-threonine containing pentapeptides are more prone to mimic β-strands than their natural Ser and Thr pentapeptide analogues. The proof of concept that these fluorinated β-strand mimics are able to disrupt protein–protein interactions involving β-sheet structures is provided. The
- CF3-threonine containing pentapeptides interact with the amyloid peptide Aβ1-42 in order to reduce the protein–protein interactions mediating its aggregation process. Keywords: aggregation; beta-sheet; fluorine; peptide; unnatural amino acid; Introduction It is estimated that 20% of administered
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