- Fluorous Mixture Synthesis of Tripeptides and Pentapeptides Using- a Fluorous-Fmoc Protection Strategy
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A liquid-phase split-type synthesis of various tripeptides and pentapeptides was conducted using a fluorous-Fmoc protection strategy. Fluorous-Fmoc reagents were effectively used as both the protecting group for the amino function and the encoding tag for the amino acid structure. Several of the synthetic peptides prepared showed high activities in an ACE inhibitory assay.
- Sugiyama, Yuya,Shirai, Ryuhei,Hirose, Masaki,Watanabe, Tomoko,Yoshida, Ayana,Endo, Natsuki,Hayashi, Toshiya,Shioiri, Takayuki,Matsugi, Masato
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p. 2187 - 2204
(2017/05/05)
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- Pressure-induced oligomerization of alanine at 25 °C
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Pressure-induced oligomerization was found from high-pressure experiments at 25 °C on alanine powder soaked in its saturated aqueous solution. The oligomerization to alanylalanine occurred at 5 GPa. The maximum yields of alanylalanine and trialanine were, respectively, 1.1 × 10-3 and 1.3 × 10-4 at 11 GPa.
- Fujimoto, Chikako,Shinozaki, Ayako,Mimura, Koichi,Nishida, Tamihito,Gotou, Hirotada,Komatsu, Kazuki,Kagi, Hiroyuki
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p. 13358 - 13361
(2015/08/24)
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- Determination of peptide backbone torsion angles using double-quantum dipolar recoupling solid-state NMR spectroscopy
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Several approaches for utilizing dipolar recoupling solid-state NMR (ssNMR) techniques to determine local structure at high resolution in peptides and proteins have been developed. However, many of these techniques measure only one torsion angle or are accurate for only certain classes of secondary structure. Additionally, the efficiency with which these dipolar recoupling experiments suppress the deleterious effects of chemical shift anisotropy (CSA) at high magnetic field strengths varies. Dipolar recoupling with a windowless sequence (DRAWS) has proven to be an effective pulse sequence for exciting double-quantum (DQ) coherences between adjacent carbonyl carbons along the peptide backbone. By allowing this DQ coherence to evolve, it is possible to measure the relative orientations of the CSA tensors and subsequently use this information to determine the Ramachandran torsion angles φ and ψ. Here, we explore the accuracies of the assumptions made in interpreting DQ-DRAWS data and demonstrate their fidelity in measuring torsion angles corresponding to a variety of secondary structures irrespective of hydrogen-bonding patterns. It is shown how a simple choice of isotopic labels and experimental conditions allows accurate measurement of backbone secondary structures without any prior knowledge. This approach is considerably more sensitive for determining structure in helices and has comparable accuracy for β-sheet and extended conformations relative to other methods. We also illustrate the ability of DQ-DRAWS to distinguish between structures in heterogeneous samples.
- Mehta, Manish A.,Eddy, Matthew T.,McNeill, Seth A.,Mills, Frank D.,Long, Joanna R.
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p. 2202 - 2212
(2008/09/18)
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- Mechanism study on the oligomerization of amino acids into peptides by phosphorus trichloride
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As treated by phosphorus trichloride, amino acids could oligomerize into polypeptides. Based on the results obtained by 31P-NMR and ESI-MS/MS, a possible reaction mechanism was proposed. The mechanism might undergo a penta-coordinated phosphorus intermediat. The activated amino acid was a five-membered cyclic penta-coordinated phosphorus intermediate. The nucleophilic attack of the amino group from an amino acid or peptide on the carbonyl group of intermediate led to the formation of peptide and released one equivalent dichloride phosphoric acid. The repetition of the reaction sequence generated a series of oligopeptides. Copyright Taylor & Francis Group, LLC.
- Zhao, Wenjie,Zhao, Dongxin,Lu, Kui
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scheme or table
p. 691 - 698
(2009/05/07)
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- Structure and dynamics of the homologous series of alanine peptides: A joint molecular dynamics/NMR study
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The φ,ψ backbone angle distribution of small homopolymeric model peptides is investigated by a joint molecular dynamics (MD) simulation and heteronuclear NMR study. Combining the accuracy of the measured scalar coupling constants and the atomistic detail of the all-atom MD simulations with explicit solvent, the thermal populations of the peptide conformational states are determined with an uncertainty of R helical conformations. No significant change in the distribution of conformers is observed with increasing chain length (Ala3 to Ala7). Trivaline samples all three major conformations significantly. Tryglycine samples the four corner regions of the Ramachandran space and exists in a slow conformational equilibrium between the cis and trans conformation of peptide bonds. The backbone angle distribution was also studied for the segment Ala3 surrounded by either three or eight amino acids on both N- and C-termini from a sequence derived from the protein hen egg white lysozyme. While the conformational distribution of the central three alanine residues in the 9mer is similar to that for the small peptides Ala3-Ala7, major differences are found for the 19mer, which significantly (30-40%) samples αR helical stuctures.
- Graf, Juergen,Nguyen, Phuong H.,Stock, Gerhard,Schwalbe, Harald
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p. 1179 - 1189
(2008/04/18)
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- The peptide formation mediated by cyanate revisited. N-carboxyanhydrides as accessible intermediates in the decomposition of N-carbamoylamino acids
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Similar to many ureas, N-carbamoylamino acids were shown to be hydrolyzed in aqueous solution through elimination mechanisms at close to neutral pH, the nucleophilic attack of water being a minor process. Two competing elimination mechanisms can take place involving either cyanate or isocyanate transient intermediates. Peptide formation was observed and attributed to the latter pathway through the intermediacy of amino acid N-carboxyanhydride (NCA). Eventually, cyanate and its precursors (including urea) unexpectedly behave as amino acid activating agents because of their ability in amino acid carbamoylation. Owing to its ability to generate a background prebiotic production of NCAs on the primitive Earth, this reaction is suggested to have contributed to the origin of life process. Copyright
- Danger, Gregoire,Boiteau, Laurent,Cottet, Herve,Pascal, Robert
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p. 7412 - 7413
(2007/10/05)
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- Small peptides as modular catalysts for the direct asymmetric aldol reaction: Ancient peptides with aldolase enzyme activity
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Simple peptides and their analogues having a primary amino group as the catalytic residue mediate the direct asymmetric intermolecular aldol reaction with high stereoselectivity and furnish the corresponding aldol products with up to 99% ee; this intrinsic ability of highly modular peptides may explain the initial molecular evolution of aldolase enzymes. The Royal Society of Chemistry 2005.
- Zou, Weibiao,Ibrahem, Ismail,Dziedzic, Pawel,Sunden, Henrik,Cordova, Armando
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p. 4946 - 4948
(2007/10/03)
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- Optimization of protocols for solid-phase synthesis on a flexible crosslinked support: Synthesis of [Leu5]enkephalin
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An optimized protocol for the solid-phase synthesis of peptides on high capacity 1,4-butanediol dimethacrylate-crosslinked polystyrene (BDDMA-PS) resin is illustrated by synthesizing [Leu5]enkephalin and hydrophobic tripeptides in both free and protected form using t-butyloxycarbonyl (Boc)/benzyl (Bzl) chemistry.
- Kumar, I. M. Krishna,Mathew, Beena
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p. 916 - 920
(2007/10/03)
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- Chromatographic method for the determination of conditional equilibrium constants for the carbamate formation reaction from amino acids and peptides in aqueous solution
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A novel and sensitive method has been developed and evaluated for the study of carbamate formation equilibria of amino acids and peptides in aqueous solution. The method is based on reversed-phase liquid chromatography with cetyltrimethylammonium bromide. The reliability of the method was established by comparing the results determined from the present study with the few data in the literature. The relaxation rate of the carbamate reaction was shown to be faster than the chromatographic distribution relaxation rate (seconds). As a result, the retention time of amine solutes is increased in the presence of CO2. Carbamate formation constants and mole fractions of carbamates at physiological pH of eleven L-α-amino acids and peptides were determined. No correlation between the formation constant and the ammonium pKa was found. There is significant dependence of the amount of a particular amino acid or peptide that exists as carbamate at pH 7.4 on the pKa of the ammonium group, however. This is due to mass action rather than reflecting the influence of pKa on the propensity of the amine to react with CO2. It is suggested that amino acids and peptides with ammonium pKa greater than 9.5 do not form significant amounts of carbamates in aqueous solution near neutral pH.
- Chen, Jian-Ge,Sandberg, Mats,Weber, Stephen G.
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p. 7343 - 7350
(2007/10/02)
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- Methyl group steric effects on the kinetics of the copper(II)-tripeptide reactions with triethylenetetramine
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Rates of reaction of triethylenetetramine (trien) with doubly deprotonated (tripeptido)cuprate(II) complexes are measured as a function of the number and position of methyl groups in the amino acid residues. Twelve tripeptides that consist of glycyl (G), L-alanyl (A), and α-aminoisobutyryl (Aib) residues are compared. The Cu(H-2Aib3)- complex reacts 8 orders of magnitude more slowly with trien than does the Cu(H-2G3)- complex. Methyl groups on the α-carbon of the second and third amino acid residues (from the amino terminus) decrease the rate of the trien substitution reaction to a much greater extent than methyl groups on the first residue. An empirical correlation between the second-order rate constant (Ktrien, M-1 s-1 at 25.0°C, pH ? 11) and the number and position of the methyl groups is found: log ktrien = 6.7 - 0.2C1 - 2.2C2 - 1.6C3, where Ci denotes the number of methyl groups in the ith amino acid residue. The enormous changes in reactivity are attributed primarily to steric effects in these ligand-ligand exchange reactions.
- Schwederski, Brigitte E.,Basile-D'Alessandro, Franco,Dickson, Peter N.,Lee, Hsiupu D.,Raycheba, John M. T.,Margerum, Dale W.
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p. 3477 - 3480
(2008/10/08)
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- Thermitase - A Thermostable Serine Protease. III. Synthesis of N-Acylated Peptide Methyl Ketones as Inhibitors Reversibly Bound to the Enzyme
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Methyl ketone derivatives of dipeptides to pentapeptides are used as suitable tools in the investigation of the non-covalent binding for subsite mapping of the active site of the enzyme.The synthesis is mainly performed by fragment condensation of N-acylated peptides or amino acids with methyl ketone derivatives of amino acids.These are prepared from the Z-protected chloromethyl ketones by catalytic hydrogenation.For the coupling steps the Z-protection is preferred.The peptide methyl ketones used in kinetic studies were N-protected by the Z, acetyl, Boc or pyroglutamyl residue.
- Fittkau, Siegfried,Jahreis, Guenther
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