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1.
New analogues of deltorphin I (DT I, Tyr‐d ‐Ala‐Phe‐Asp‐Val‐Val‐Gly‐NH2), with the d ‐Ala residue in position 2 replaced by α‐methyl‐β‐azido(amino, 1‐pyrrolidinyl, 1‐piperidinyl or 4‐morpholinyl)alanine, were synthesized by a combination of solid‐phase and solution methods. All ten new analogues were tested for receptor affinity and selectivity to μ‐ and δ‐opioid receptors. The affinity of analogues containing (R) or (S)‐α‐methyl‐β‐azidoalanine in position 2 to δ‐receptors strongly depended on the chirality of the α,α‐disubstituted residue. Peptide II , containing (S)‐α‐methyl‐β‐azidoalanine in position 2, displayed excellent δ‐receptor selectivity with its δ‐receptor affinity being only three times lower than that of DT I. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

2.
A series of Fmoc‐Phe(4‐aza‐C60)‐OH of fullerene amino acid derived peptides have been prepared by solid phase peptide synthesis, in which the terminal amino acid, Phe(4‐aza‐C60)‐OH, is derived from the dipolar addition to C60 of the Fmoc‐Nα‐protected azido amino acids derived from phenylalanine: Fmoc‐Phe(4‐aza‐C60)‐Lys3‐OH ( 1 ), Fmoc‐Phe(4‐aza‐C60)‐Pro‐Hyp‐Lys‐OH ( 2 ), and Fmoc‐Phe(4‐aza‐C60)‐Hyp‐Hyp‐Lys‐OH ( 3 ). The inhibition constant of our fullerene aspartic protease PRIs utilized FRET‐based assay to evaluate the enzyme kinetics of HIV‐1 PR at various concentrations of inhibitors. Simulation of the docking of the peptide Fmoc‐Phe‐Pro‐Hyp‐Lys‐OH overestimated the inhibition, while the amino acid PRIs were well estimated. The experimental results show that C60‐based amino acids are a good base structure in the design of protease inhibitors and that their inhibition can be improved upon by the addition of designer peptide sequences. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

3.
Aydogan C  Denizli A 《Chirality》2012,24(8):606-609
This article describes the development of a polybutylmethacrylate‐based monolithic capillary column as a chiral stationary phase. The chiral monolithic column was prepared by polymerization of butyl methacrylate (BMA), ethylene dimethacrylate (EDMA), and N‐methacryloyl‐l ‐glutamic acid (MAGA) in the presence of porogens. The porogen mixture included N,N‐dimethyl formamide and phosphate buffer. MAGA was used as a chiral selector. The effect of MAGA content was investigated on electrochromatographic enantioseparation of d,l ‐histidine, d,l ‐tyrosine, d,l ‐phenyl alanine, and d,l ‐glutamic acid. The effect of acetonitrile (ACN) content in mobile phase on electro‐osmotic flow was also investigated. It was demonstrated that the poly(BMA‐EDMA‐MAGA) monolithic chiral column can be used for the electrochromatographic enantioseparation of amino acids by capillary electrochromatography (CEC). The mobile phase was ACN/10 mM phosphate buffer (45:55%) adjusted to pH 2.7. It was observed that l ‐enantiomers of the amino acids migrated before d ‐enantiomers. The separation mechanism of electrochromatographic enantioseparation of amino acids in CEC is discussed. Chirality 24:606–609, 2012. © 2012 Wiley Periodicals, Inc.  相似文献   

4.
Insect cells are useful for the high‐yield production of recombinant proteins including chemokines and membrane proteins. In this study, we developed an insect cell‐based system for incorporating non‐natural amino acids into proteins at specific sites. Three types of promoter systems were constructed, and their efficiencies were compared for the expression of the prokaryotic amber suppressor tRNATyr in Drosophila melanogaster Schneider 2 cells. When paired with a variant of Escherichia coli tyrosyl‐tRNA synthetase specific for 3‐iodo‐L ‐tyrosine, the suppressor tRNA transcribed from the U6 promoter most efficiently incorporated the amino acid into proteins in the cells. The transient and stable introductions of these prokaryotic molecules into the insect cells were then compared in terms of the yield of proteins containing non‐natural amino acids, and the “transient” method generated a sevenfold higher yield. By this method, 4‐azido‐L ‐phenylalanine was incorporated into human interleukin‐8 at a specific site. The yield of the azido‐containing IL‐8 was 1 μg/1 mL cell culture, and the recombinant protein was successfully labeled with a fluorescent probe by the Staudinger–Bertozzi reaction.  相似文献   

5.
Enantiomeric separations of N‐phthaloyl (N‐PHT), N‐tetrachlorophthaloyl (N‐TCPHT), and N‐naphthaloyl (N‐NPHT) α‐amino acids and their esters were examined on several kinds of polysaccharide‐derived chiral stationary phases (CSPs). Resolution capability of CSPs was greater Chiralcel OF than the others for N‐PHT and N‐NPHT α‐amino acids and their esters. In N‐TCPHT α‐amino acids and their esters, good enantioselectivities showed Chiralcel OG for N‐TCPHT α‐amino acids, Chiralpak AD for N‐TCPHT α‐amino acid methyl esters, and Chiralcel OD for N‐TCPHT α‐amino acid ethyl esters, respectively. From the results of liquid chromatography and computational chemistry, it is concluded that l ‐form is preferred and more retained with electrostatic interaction in case of interaction between N‐PHT α‐amino acid derivatives and Chiralcel OF, N‐TCPHT α‐amino acid derivatives and Chiralcel OD, and N‐NPHT α‐amino acid derivatives and Chiracel OF. On the other hand, d ‐form is preferred and more retained with van der Waals interaction in case of interaction between N‐TCPHT α‐amino acid ester derivatives and Chiralcel OG and Chiralpak AD. Chirality 24:1037–1046, 2012. © 2012 Wiley Periodicals, Inc.  相似文献   

6.
7.
Solid‐phase synthesis allows for the preparation of some complex cysteine‐containing peptides with both a high yield and purity. However, side reactions during chain elongation such as modification of amino acid residues have been found in C‐terminal cysteine peptides. We identified 3‐(1‐piperidinyl)‐alanine peptides, corroborated the mechanism of the side reaction, and introduced an efficient approach for the Fmoc‐based synthesis of C‐terminal cysteine peptides using an aryl hydrazine linker. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

8.
ROS, continuously produced in cells, can reversibly or irreversibly oxidize proteins, lipids, and DNA. At the protein level, cysteine, methionine, tryptophan, and tyrosine residues are particularly prone to oxidation. Here, we describe the solid phase synthesis of peptides containing four different oxidation products of tryptophan residues that can be formed by oxidation in proteins in vitro and in vivo: 5‐HTP, Oia, Kyn, and NFK. First, we synthesized Oia and NFK by selective oxidation of tryptophan and then protected the ${\bf \alpha}$ ‐amino group of both amino acids, and the commercially available 5‐HTP, with Fmoc‐succinimide. High yields of Fmoc‐Kyn were obtained by acid hydrolysis of Fmoc‐NFK. All four Fmoc derivatives were successfully incorporated, at high yields, into three different peptide sequences from skeletal muscle actin, creatin kinase (M‐type), and ${\bf \beta}$ ‐enolase. The correct structure of all modified peptides was confirmed by tandem mass spectrometry. Interestingly, isobaric peptides containing 5‐HTP and Oia were always well separated in an acetonitrile gradient with TFA as the ion‐pair reagent on a C18‐phase. Such synthetic peptides should prove useful in future studies to distinguish isobaric oxidation products of tryptophan. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

9.
β‐Amino acids containing α,β‐hybrid peptides show great potential as peptidomimetics. In this paper, we describe the synthesis and affinity to μ‐opioid and δ‐opioid receptors of α,β‐hybrids, analogs of the tetrapeptide Tyr‐ d ‐Ala‐Phe‐Phe‐NH2 (TAPP). Each amino acid was replaced with an l ‐ or d ‐β3h‐amino acid. All α,β‐hybrids of TAPP analogs were synthesized in solution and tested for affinity to μ‐opioid and δ‐opioid receptors. The analog Tyr‐β3h‐ d ‐Ala‐Phe‐PheNH2 was found to be as active as the native tetrapeptide. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

10.
The relationship between the conformation and biological activity of the peptide allosteric modulator of the interleukin‐1 receptor 101.10 (D ‐Arg‐D ‐Tyr‐D ‐Thr‐D ‐Val‐D ‐Glu‐D ‐Leu‐D ‐Ala‐NH2) has been studied using (R)‐ and (S)‐Bgl residues. Twelve Bgl peptides were synthesized using (R)‐ and (S)‐cyclic sulfamidate reagents derived from L ‐ and D ‐aspartic acid in an optimized Fmoc‐compatible protocol for efficient lactam installment onto the supported peptide resin. Examination of these (R)‐ and (S)‐Bgl 101.10 analogs for their potential to inhibit IL‐1β‐induced thymocyte cell proliferation using a novel fluorescence assay revealed that certain analogs exhibited retained and improved potency relative to the parent peptide 101.10. In light of previous reports that Bgl residues may stabilize type II′β‐turn‐like conformations in peptides, CD spectroscopy was performed on selected compounds to identify secondary structure necessary for peptide biological activity. Results indicate that the presence of a fold about the central residues of the parent peptide may be important for activity. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

11.
This work reports an efficient Lewis acid catalysed N‐methylation procedure of lipophilic α‐amino acid methyl esters in solution phase. The developed methodology involves the use of the reagent system AlCl3/diazomethane as methylating agent and α‐amino acid methyl esters protected on the amino function with the (9H‐fluoren‐9‐yl)methanesulfonyl (Fms) group. The removal of Fms protecting group is achieved under the same conditions to those used for Fmoc removal. Thus the Fms group can be interchangeable with the Fmoc group in the synthesis of N‐methylated peptides using standard Fmoc‐based strategies. Finally, the absence of racemization during the methylation reaction and the removal of Fms group were demonstrated by synthesising a pair of diastereomeric dipeptides. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

12.
Chemoreceptors play a central role in chemotaxis, allowing bacteria to detect chemical gradients and bias their swimming behavior in order to navigate toward favorable environments. The genome of the kiwifruit pathogen, Pseudomonas syringae pv. actinidiae (Psa) strain NZ‐V13 encodes 43 predicted chemoreceptors, none of which has been characterized. We developed a high‐throughput fluorescence‐based thermal shift assay for identifying the signal molecules that are recognized by a given chemoreceptor ligand binding domain (LBD). Using this assay, we characterized the ligand binding profiles of three Psa homologs of the P. aeruginosa PAO1 amino acid chemoreceptors PctA, PctB and PctC. Each recombinant LBD was screened against 95 potential ligands. The three Psa homologs, named pscA, pscB and pscC (P s a c hemoreceptors A , B and C ) bound 3, 10 and 3 amino acids respectively. In each case, their binding profiles were distinct from their P. aeruginosa PAO1 homologs. Notably, Psa PscA‐LBD only bound the acidic amino acids l ‐aspartate, d ‐aspartate and l ‐glutamate, whereas P. aeruginosa PctA‐LBD binds all of the l ‐proteinogenic amino acids except for l ‐aspartate and l ‐glutamate. A combination of homology modeling, site‐directed mutagenesis and functional screening identified a single amino acid residue in the Psa PscA‐LBD (Ala146) that is critically important for determining its narrow specificity.  相似文献   

13.
N‐[1‐(4‐(4‐fluorophenyl)‐2,6‐dioxocyclohexylidene)ethyl] (Fde) protected amino acids have been prepared and applied in solid‐phase peptide synthesis monitored by gel‐phase 19F NMR spectroscopy. The Fde protective group could be cleaved with 2% hydrazine or 5% hydroxylamine solution in DMF as determined with gel‐phase 19F NMR spectroscopy. The dipeptide Ac‐L ‐Val‐L ‐Val‐NH2 12 was constructed using Fde‐L ‐Val‐OH and no noticeable racemization took place during the amino acid coupling with N,N′‐diisopropylcarbodiimide and 1‐hydroxy‐7‐azabenzotriazole or Fde deblocking. To extend the scope of Fde protection, the hydrophobic nonapeptide LLLLTVLTV from the signal sequence of mucin MUC1 was successfully prepared using Fde‐L ‐Leu‐OH at diagnostic positions. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

14.
The 2‐(o‐nitrophenyl)‐propyl (NPP) group is used as caging group to mask the nucleobases adenine and cytosine in N‐(2‐aminoethyl)glycine peptide nucleic acids (aeg‐PNA). The adeninyl and cytosinyl nucleo amino acid building blocks Fmoc‐aNPP‐aeg‐OH and Fmoc‐cNPP‐aeg‐OH were synthesized and incorporated into PNA sequences by Fmoc solid phase synthesis relying on high stability of the NPP nucleobase protecting group toward Fmoc‐cleavage, coupling, capping, and resin cleavage conditions. Removal of the nucleobase caging group was achieved by UV‐LED irradiation at 365 nm. The nucleobase caging groups provided sterical crowding effecting the Watson–Crick base pairing, and thereby, the PNA double strand stabilities. Duplex formation can completely be suppressed for complementary PNA containing caging groups in both strands. PNA/PNA recognition can be completely restored by UV light‐triggered release of the photolabile protecting group. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

15.
‘Chemical ligation’ – the regioselective and chemoselective covalent condensation of unprotected peptide segments – has enabled the synthesis of polypeptide chains of more than 200 amino acids. An efficient total chemical synthesis of the insulin molecule has been devised on the basis of a key ester‐linked intermediate that is chemically converted to fully active human insulin. Enzyme molecules of defined covalent structure and with full enzymatic activity have been prepared and characterized by high‐resolution X‐ray crystallography. A ‘glycoprotein mimetic’ of defined chemical structure and with a mass of 50,825 Da, has been prepared and shown to have full biological activity and improved pharmacokinetic properties. d ‐Protein molecules that are the mirror images of proteins found in the natural world have been prepared by total chemical synthesis. Racemic protein mixtures, consisting of the d ‐enantiomers and l ‐enantiomers of a protein molecule, form highly ordered centrosymmetric crystals with great ease; this has enabled the determination of the crystal structures of recalcitrant protein molecules. A protein with a novel linear‐loop covalent topology of the peptide chain has been designed and synthesized and its structure determined by facile crystallization as the quasi‐racemate with the d ‐form of the native protein molecule. We have developed an optimized total chemical synthesis of biologically active vascular endothelial growth factor‐A; total synthesis of the mirror‐image protein will be used to systematically develop d ‐protein antagonists of this important growth factor. The total chemical synthesis of proteins is now a practical reality and enables access to a new world of protein molecules. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

16.
Detailed studies comparing solid‐supported l ‐ or d ‐amino acid adhesion peptides based on the sequence KLHRIRA were performed. Stability towards proteases and levels of cellular adhesion to the otherwise inert surface of PEGA resin were compared by using fluorescently labelled peptides. A clear difference in the peptide stability towards cleavage by subtilisin, trypsin, or papain was observed. However, all of the on‐bead peptides provided an optimal surface for cell adhesion and proliferation. In long‐term experiments, these properties were still found to be similar on the resins modified either with l ‐ or with d‐ amino acids and unaffected by the nature of their fluorescence labelling at either terminus. These results support that the more accessible l ‐amino acids can be utilized for cell adhesion experiments and confirm the nonspecific interaction mechanism of cell binding to these peptides on the bead surface. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

17.
A strategy was developed to directly assemble 4‐amino‐1,2,4,5‐tetrahydro‐indolo[2,3‐c]‐azepin‐3‐ones on solid‐phase‐supported peptide sequences. Fmoc‐ and Boc‐based strategies were investigated. The Fmoc‐strategy approach strongly depends on the peptide sequence being synthesized while the Boc‐based synthesis leads to excellent results for all the selected peptide analogs. The method was applied to prepare Aia‐analogs of several bioactive peptides containing one or more Trp‐residues which were shown to be important for biological recognition. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

18.
Peptidoglycan (PG) is an essential, envelope‐fortifying macromolecule of eubacterial cell walls. It is a large polymer with multiple glycan strands interconnected by short peptide chains forming a sac‐like structure around cytoplasmic membrane. In most bacteria, the composition of the peptide chain is well‐conserved and distinctive; in E. coli, the peptide chain length varies from two to five amino acids with a tetrapeptide consisting of L‐alanine – D‐glutamic acid – meso‐diaminopimelic acid – D‐alanine. However, it is not known how bacteria conserve the composition and sequence of peptide chains of PG. Here, we find that a conserved open reading frame of unknown function, YfiH (renamed PgeF) contributes to the maintenance of peptide composition in E. coli. Using genetic, biochemical and mass spectrometrical analyses we demonstrate that absence of yfiH results in incorporation of non‐canonical amino acids, L‐serine or glycine in place of L‐alanine in PG sacculi leading to β‐lactam – sensitivity, lethality in mutants defective in PG remodelling or recycling pathways, altered cell morphology and reduced PG synthesis. yfiH orthologs from other Gram‐positive genera were able to compensate the absence of yfiH in E. coli indicating a conserved pathway in bacterial kingdom. Our results suggest editing/quality control mechanisms exist to maintain composition and integrity of bacterial peptidoglycan.  相似文献   

19.
A pair of l ‐leucine (l ‐Leu) and d ‐leucine (d ‐Leu) was incorporated into α‐aminoisobutyric acid (Aib) peptide segments. The dominant conformations of four hexapeptides, Boc‐l ‐Leu‐Aib‐Aib‐Aib‐Aib‐l ‐Leu‐OMe (1a), Boc‐d ‐Leu‐Aib‐Aib‐Aib‐Aib‐l ‐Leu‐OMe (1b), Boc‐Aib‐Aib‐l ‐Leu‐l ‐Leu‐Aib‐Aib‐OMe (2a), and Boc‐Aib‐Aib‐d ‐Leu‐l ‐Leu‐Aib‐Aib‐OMe (2b), were investigated by IR, 1H NMR, CD spectra, and X‐ray crystallographic analysis. All peptides 1a,b and 2a,b formed 310‐helical structures in solution. X‐ray crystallographic analysis revealed that right‐handed (P) 310‐helices were present in 1a and 1b and a mixture of right‐handed (P) and left‐handed (M) 310‐helices was present in 2b in their crystalline states. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

20.
The O‐acyl isopeptide method was developed for the efficient preparation of difficult sequence‐containing peptide. Furthermore, development of the O‐acyl isodipeptide unit for Fmoc chemistry simplified its synthetic procedure by solid‐phase peptide synthesis. Here, we report a novel isodipeptide unit for Boc chemistry, and the unit was successfully applied to the synthesis of amyloid β peptide. Combination of Boc chemistry and the isodipeptide unit would be an effective method for the synthesis of many difficult peptides. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.  相似文献   

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