- A clickable, highly soluble oligopeptide that easily forms organogels
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An artificial peptide, N3-GVGV-OMe (G, glycine; V, valine), which mimics the repeating GAGA (A, alanine) sequence in Bombix Mori silk, was synthesised via solution-phase synthesis. Compared with N3-GAGA-OMe sequence, N3-GVGV-OMe showed high solubility in common organic solvents (such as CHCl3, THF and CH2Cl2), and easily formed organogels simply by adding poor solvents (such as toluene or ether) to the peptide solution at room temperature. The hierarchical nanostructure of N3-GVGV-OMe organogel was dependent on the nature of the poor solvents, although in all cases, β-sheets were formed exclusively. Gels formed in ether showed higher level hierarchical assembly, as evidenced by AFM and CD studies. Solution-state FT-IR analysis showed that the pre-organisation of the peptides in solution was not significant, and well-defined antiparallel β-sheets were formed after the addition of the poor solvent. The high solubility and strong tendency for self-assembly of N3-GVGV-OMe, together with its terminal azide group, might facilitate the modification of functional organic molecules even macromolecules for better nanostructure control.
- Gong, Ruiying,Song, Yubao,Guo, Zongxia,Li, Ming,Jiang, Yi,Wan, Xiaobo
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Read Online
- Synthesis of Histidine-Containing Oligopeptides via Histidine-Promoted Peptide Ligation
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Histidine-containing peptides are valuable therapeutic agents for a treatment of neurodegenerative diseases. However, the synthesis of histidine-containing peptides is not trivial due to the potential of imidazole sidechain of histidine to act as a nucleophile if unprotected. A peptide ligation method utilizing the imidazole sidechain of histidine has been developed. The key imidazolate intermediate that acts as an internal acyl transfer catalyst during ligation is generated by deprotonation. Transesterification with amino acids or peptides tethered with C-terminal thioester followed by N→N acyl shifts led to the final ligated products. A range of histidine-containing dipeptides could be synthesized in moderate to good yields via this method without protecting the imidazole sidechain. The protocol was further extended to tripeptide synthesis via a long-range N→N acyl transfer, and tetrapeptide synthesis.
- Huang, Kai-Jin,Huang, Yi-Chen,Lin, Yuya A.
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supporting information
p. 400 - 403
(2018/02/21)
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- CASPASE PROBES FOR DETECTION OF APOPTOSIS
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The present disclosure relates to glycine-containing probes that are capable of binding to active caspases and can be used for detecting apoptosis. In particular, the probes can be used to determine the degree or incidence of caspase-mediated apoptosis and conditions associated therewith. In one embodiment, the probes are cell permeable and function intracellularly. The disclosure includes a caspase probe having the formula: R1-X-R2 wherein R1 is absent, a detectable or non-detectable N-terminal group, or a chelator; X is a group that recognizes a caspase; and R2 is a reactive group that binds to a caspase. The caspase probes can be used for purposes of diagnostic testing, research, and drug development, among other uses. The present disclosure further relates to compositions comprising at least one probe and an excipient, as well as kits comprising at least one probe and instructions for use.
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Page/Page column 39
(2016/05/24)
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- Total syntheses of 28,29-diepi-arenamide A, 29-epi-arenamide A, and 28-epi-arenamide A
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This communication describes the synthesis of stereochemical analogs of arenamide A, a 19-membered cytotoxic depsipeptide isolated from the fermentation broth of a marine bacterial strain Salinispora arenicola. The key steps are diastereoselective aldol r
- Jithender Reddy, V.,Pradhan, Tapan Kumar,Ghosh, Subhash
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p. 6148 - 6150,3
(2020/08/20)
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- Guanidine hydrochloride as an organocatalyst for N-Boc protection of amino groups
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A simple and efficient method for the chemoselective N-Boc protection of the amine moiety in a variety of compounds is described using di-tert-butyl dicarbonate and guanidine hydrochloride as an organocatalyst in ethanol at 35-40°C. Selective mono-N-Boc protection of diamines and chemoselective protection of hydroxylamines without formation of any side products is achieved. Amino acids and peptides are N-Boc protected efficiently in excellent yields under convenient reaction conditions.
- Jahani, Fatemeh,Tajbakhsh, Mahmood,Golchoubian, Hamid,Khaksar, Samad
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supporting information; experimental part
p. 1260 - 1264
(2011/04/15)
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- Bioinspired modular synthesis of elastin-mimic polymers to probe the mechanism of elastin elasticity
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Bioinspired modular synthesis of elastin-mimic polymers (EMPs) is achieved via Cu-catalyzed alkyne-azide cyclization (CuAAC). By changing the module, EMPs with different secondary structures determined by circular dichroism (CD) spectra in trifluoroethanol (TFE) solution are obtained. The EMPs are characterized by measuring the lower critical solution temperatures (LSCTs) and the bulk mechanic properties under the conditions of both dry and hydrated forms. The unique molecular design enables us to probe mechanistic questions and assess the structure-property relationship of the EMPs. Our results indicate that, instead of a highly organized secondary structure, hydrophobic hydration is critical for the elasticity of EMPs.
- Chen, Yulin,Guan, Zhibin
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supporting information; experimental part
p. 4577 - 4579
(2010/06/17)
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- The first total synthesis of emericellamide A
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A highly convergent asymmetric total synthesis of emericellamide A, a 19-membered antibacterial depsipeptide isolated from the co-culture of an Emericella sp. (strain CNL-878) and a Salinispora arenicola (strain CNH-665) is described.
- Ghosh, Subhash,Pradhan, Tapan Kumar
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p. 3697 - 3700
(2008/09/19)
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- Synthetic studies on cyclic octapeptides: Yunnanin F and Hymenistatin
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Two biologically active cyclic peptides, Yunnanin F 8 and Hymenistatin 16 were synthesized and the structures were established on the basis of analytical, IR, NMR and mass spectral data. The newly synthesized compounds were screened for their antimicrobia
- Poojary, Boja,Belagali, Shiddappa L.
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p. 407 - 412
(2007/10/03)
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- Phenylhydrazide as an enzyme-labile protecting group in peptide synthesis
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The enzymatic cleavage of amino acid phenylhydrazides with the enzyme tyrosinase (EC 1.14.18.1) offers a new, mild, and selective method for C-terminal deprotection of peptides. The advantages of the described methodology are the very mild oxidative removal of the protecting group at room temperature and pH 7, a high chemo- and regioselectivity, and the availability of the biocatalyst. Even in oxygen-saturated solution, the oxidation of sensitive methionine residues was not observed. These features make the methodology suitable for the synthesis of sensitive peptide conjugates. Mechanistic data suggest that the hydrolysis of the oxidized adducts proceeds by a free-radical mechanism.
- Voelkert, Martin,Koul, Surrinder,Mueller, Gernot H.,Lehnig, Manfred,Waldmann, Herbert
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p. 6902 - 6910
(2007/10/03)
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- Design, synthesis, and conformational analysis of a novel macrocyclic HIV- protease inhibitor
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Design modifications to the lead HIV-PR inhibitor 1 (MDL 73,669, K(i) = 5 nM) have been postulated based on a computational model of the 1/HIV-PR complex. A novel macrocyclic inhibitor 8 (MDL 104,168) wherein the P1 and P3 side chain
- Podlogar,Farr,Friedrich,Tarnus,Huber,Cregge,Schirlin
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p. 3684 - 3692
(2007/10/02)
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