Search results for "Pentapeptide repeat"
showing 10 items of 11 documents
Probing the Folding of Peptide–Polymer Conjugates Using the π-Dimerization of Viologen End-Groups
2020
The synthesis of a foldable viologen-functionalized peptide–polymer conjugate is presented. The ABA-type triblock conjugate with a PEG polymer was capped with a FHFHF pentapeptide sequence and further modified with a viologen building block at both chain ends. The pH-responsive peptide domains fold into an intermediate structure inducing close proximity of the viologen units, which upon a reduction step form π-dimers of the radical cation. Overall the intramolecular folding and intermolecular self-assembly process leads to the formation of supramolecular nanorods. Mixing of viologen-peptide–polymer conjugates with unfunctionalized conjugates leads to crosslinking of the nanorods and hydroge…
Secondary Structure-Driven Hydrogelation Using Foldable Telechelic Polymer-Peptide Conjugates.
2018
The synthesis of ABA and ABA' triblock polyethylene glycol-and polysarcosine-peptide conjugates is reported. The A/A' peptides are based on phenylalanine(F)-histidine(H) pentapeptide sequences FHFHF, which promote pH-switchable β-sheet self-assembly into nanorods in water. Only parallel β-sheet-driven folding and intermolecular assembly using ABA triblock polymer-peptide conjugates leads to interstrand cross-linking and hydrogelation, highlighting the impact of supramolecular interactions-directed structure formation at the nano- and mesoscopic level.
Folding induced supramolecular assembly into pH-responsive nanorods with a protein repellent shell
2018
We report the synthesis of ABA' triblock peptide-polysarcosine-peptide conjugates featuring two complementary phenylalanine-histidine pentapeptide strands A/A'. These sequences encode for antiparallel beta-sheet formation into folded conjugates, which promote the self-assembly into polysarcosine-shielded core-shell nanorods. These do not cause aggregation of serum proteins in human blood plasma underlining an enhanced stability.
Convenient High Yielding Gram Scale Solution Synthesis of Methionine-Enkephalin.
1998
A simple, large-scale synthesis of a cytokine, methionine-enkephalin, Tyr-Gly-Gly-Phe-Met, has been elaborated. Classical solution peptide chemistry methods without protection of amino acid side-chain functions and 1+(2+2) segment condensation were used. A nine-step synthesis from commercial amino acid derivatives was developed with yields ranging from 86% to 99%, averaging 92%. The purity of all intermediates was found to be 99.0-100% by HPLC. The process has been used to prepare greater than 150 g quantities of the pentapeptide as a monohydrate of 100% purity. Hydantoin formation was observed during saponification of Boc-Tyr-Gly-Gly-Phe-Met-OMe and minimised.
N-[tert-Butoxycarbonylglycyl-(Z)-α,β-dehydrophenylalanylglycyl-(E)-α,β-dehydrophenylalanylphenylalanyl]-4-nitroaniline ethanol solvate
2005
The alpha,beta-dehydrophenylalanine residues influence the conformation of the title pentapeptide Boc0-Gly1-Delta(Z)Phe2-Gly3-Delta(E)Phe4-L-Phe5-p-NA ethanol solvate, C42H43N7O9.C2H5OH. The first unsaturated phenylalanyl (Delta(Z)Phe2) and the third glycyl (Gly3) residues form a type I beta turn, while the second unsaturated phenylalanyl (Delta(E)Phe4) and the last phenylalanyl (L-Phe5) residues are part of a type II beta turn. All the amino acids in the peptide are linked trans to one another. The crystal structure is stabilized by intra- and intermolecular hydrogen bonds.
N‐[tert‐Butoxycarbonylglycyl‐(Z)‐α,β‐dehydrophenylalanylglycyl‐(E)‐α,β‐dehydrophenylalanyl]glycine methyl ester dihydrate
2006
The title pentapeptide, Boc0—Gly1–ΔZPhe2—Gly3–ΔEPhe4—Gly5—OMe, C30H35N5O8·2H2O, adopts the type I β-turn conformation for the ΔZPhe2—Gly3 residues. It is stabilized by a 4\rightarrow1 intramolecular hydrogen bond between the ΔEPhe4 NH and Gly1 CO groups. All the amino acid residues in the pentapeptide sequence are linked trans to each other. The crystal structure is stabilized by intra- and intermolecular hydrogen bonds.
Identification, Characterization and Synthesis of Natural Parasitic Cysteine Protease Inhibitors – More Potent Falcitidin Analogs
2021
ABSTRACTProtease inhibitors represent a promising therapeutic option for the treatment of parasitic diseases such as malaria and human African trypanosomiasis. Falcitidin was the first member of a new class of inhibitors of falcipain-2, a cysteine protease of the malaria parasite Plasmodium falciparum. Using a metabolomics dataset of 25 Chitinophaga strains for molecular networking enabled identification of over 30 natural analogs of falcitidin. Based on MS/MS spectra, they vary in their amino acid chain length, sequence, acyl residue, and C-terminal functionalization; therefore, they were grouped into the four falcitidin peptide families A-D. The isolation, characterization and absolute st…
Synthesis of the Glycopeptide Partial Sequence A80-A84 of Human Fibroblast Interferon
1985
The glycopentapeptide H-(GlcNAcβ1-)Asn-Glu-Thr-Ile-Val-OH (10) representing the partial sequence A80–A84 of human fibroblast interferon was synthesized using the newly developed allyl-ester protection of carboxy functions. The allyl esters, which are stable to acids and to bases, can be cleaved under very mild, neutral conditions using tris(triphenylphosphine)rhodium(I) chloride or tetrakis(triphenylphosphine)palladium(0) as a catalyst. This synthetic method opens up a preparative route to glycopeptide model structures of glycoproteins of high biological interest.
Antilisterial peptides from Spanish dry-cured hams: Purification and identification.
2016
The typical Spanish dry-cured ham has a particular sensory quality that makes it a distinctive food, highly appreciated for consumers worldwide. Its particular physicochemical properties, such as high salt content and reduced water activity contribute to their shelf-stability. However, post-processing actions carried out for the commercialization of these products such as slicing may increase the risk of development of pathogenic microorganisms as Listeria monocytogenes. During ripening, muscle proteins are hydrolyzed by muscle peptidases releasing peptides and free amino acids. Some of these peptides have been described to exert biological activities such as antioxidant and ACE-inhibition.…
A new metallothionein gene from the giant keyhole limpet Megathura crenulata.
2003
Abstract Metallothioneins (MTs) are small soluble proteins ubiquitously expressed in animals and plants. Different isoforms are present in deuterostomes and protostomes. They do not differ greatly in primary structure, but are clearly distinguishable. Here, I present the gene and the complete cDNA of a novel MT from the mollusk Megathura crenulata . This protein is closely related to the Cu-inducible MTs of the vineyard snail Helix pomatia , but has also some minor sequence features typical of Cd-inducible isoforms of H . pomatia and other molluscs. Overall, the deduced primary structure is similar to the known molluscan MTs, but in addition possesses an insertion of 5 amino acids not found…